Trigonometric and Hyperbolic Functions

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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Trigonometric and Hyperbolic Functions
Bernd Schröder
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Introduction
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Introduction
1. For real numbers θ we have eiθ = cos(θ ) + i sin(θ ).
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Introduction
1. For real numbers θ we have eiθ = cos(θ ) + i sin(θ ).
2. Replacing θ with −θ we obtain e−iθ = cos(θ ) − i sin(θ ).
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Introduction
1. For real numbers θ we have eiθ = cos(θ ) + i sin(θ ).
2. Replacing θ with −θ we obtain e−iθ = cos(θ ) − i sin(θ ).
(Remember that the cosine is even and the sine is odd.)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Introduction
1. For real numbers θ we have eiθ = cos(θ ) + i sin(θ ).
2. Replacing θ with −θ we obtain e−iθ = cos(θ ) − i sin(θ ).
(Remember that the cosine is even and the sine is odd.)
eiθ + e−iθ
3. Adding the two and dividing by 2 gives cos(θ ) =
.
2
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Introduction
1. For real numbers θ we have eiθ = cos(θ ) + i sin(θ ).
2. Replacing θ with −θ we obtain e−iθ = cos(θ ) − i sin(θ ).
(Remember that the cosine is even and the sine is odd.)
eiθ + e−iθ
3. Adding the two and dividing by 2 gives cos(θ ) =
.
2
eiθ − e−iθ
.
4. Subtracting the two and dividing by 2i gives sin(θ ) =
2i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Introduction
1. For real numbers θ we have eiθ = cos(θ ) + i sin(θ ).
2. Replacing θ with −θ we obtain e−iθ = cos(θ ) − i sin(θ ).
(Remember that the cosine is even and the sine is odd.)
eiθ + e−iθ
3. Adding the two and dividing by 2 gives cos(θ ) =
.
2
eiθ − e−iθ
.
4. Subtracting the two and dividing by 2i gives sin(θ ) =
2i
5. The right sides above make sense for all complex numbers.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cos(z) =
Bernd Schröder
Trigonometric and Hyperbolic Functions
eiz + e−iz
2
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cos(z) =
eiz + e−iz
2
sin(z) =
eiz − e−iz
.
2i
and
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
This Time, All Common Identities Carry Over
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
This Time, All Common Identities Carry Over
1. sin(z1 + z2 ) = sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
This Time, All Common Identities Carry Over
1. sin(z1 + z2 ) = sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
2. cos(z1 + z2 ) = cos(z1 ) cos(z2 ) − sin(z1 ) sin(z2 )
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
This Time, All Common Identities Carry Over
1. sin(z1 + z2 ) = sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
2. cos(z1 + z2 ) = cos(z1 ) cos(z2 ) − sin(z1 ) sin(z2 )
3. sin2 (z) + cos2 (z) = 1
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
This Time, All Common Identities Carry Over
1.
2.
3.
4.
sin(z1 + z2 ) = sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
cos(z1 + z2 ) = cos(z1 ) cos(z2 ) − sin(z1 ) sin(z2 )
sin2 (z) + cos2 (z) = 1
sin(z + 2π) = sin(z)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
This Time, All Common Identities Carry Over
1.
2.
3.
4.
5.
sin(z1 + z2 ) = sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
cos(z1 + z2 ) = cos(z1 ) cos(z2 ) − sin(z1 ) sin(z2 )
sin2 (z) + cos2 (z) = 1
sin(z + 2π) = sin(z)
cos(z + 2π) = cos(z)
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
eiz1 − e−iz1 eiz2 + e−iz2 eiz1 + e−iz1 eiz2 − e−iz2
=
+
2i
2
2
2i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
eiz1 − e−iz1 eiz2 + e−iz2 eiz1 + e−iz1 eiz2 − e−iz2
=
+
2i
2
2
2i
1 i(z1 +z2 )
+ ei(z1 −z2 ) − ei(−z1 +z2 ) − e−i(z1 +z2 )
e
=
4i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
eiz1 − e−iz1 eiz2 + e−iz2 eiz1 + e−iz1 eiz2 − e−iz2
=
+
2i
2
2
2i
1 i(z1 +z2 )
+ ei(z1 −z2 ) − ei(−z1 +z2 ) − e−i(z1 +z2 )
e
=
4i
+ ei(z1 +z2 ) − ei(z1 −z2 ) + ei(−z1 +z2 ) − e−i(z1 +z2 )
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
eiz1 − e−iz1 eiz2 + e−iz2 eiz1 + e−iz1 eiz2 − e−iz2
=
+
2i
2
2
2i
1 i(z1 +z2 )
+ ei(z1 −z2 ) − ei(−z1 +z2 ) − e−i(z1 +z2 )
e
=
4i
+ ei(z1 +z2 ) − ei(z1 −z2 ) + ei(−z1 +z2 ) − e−i(z1 +z2 )
1 i(z1 +z2 )
=
2e
− 2e−i(z1 +z2 )
4i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
eiz1 − e−iz1 eiz2 + e−iz2 eiz1 + e−iz1 eiz2 − e−iz2
=
+
2i
2
2
2i
1 i(z1 +z2 )
+ ei(z1 −z2 ) − ei(−z1 +z2 ) − e−i(z1 +z2 )
e
=
4i
+ ei(z1 +z2 ) − ei(z1 −z2 ) + ei(−z1 +z2 ) − e−i(z1 +z2 )
ei(z1 +z2 ) − e−i(z1 +z2 )
1 i(z1 +z2 )
=
2e
− 2e−i(z1 +z2 ) =
4i
2i
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
eiz1 − e−iz1 eiz2 + e−iz2 eiz1 + e−iz1 eiz2 − e−iz2
=
+
2i
2
2
2i
1 i(z1 +z2 )
+ ei(z1 −z2 ) − ei(−z1 +z2 ) − e−i(z1 +z2 )
e
=
4i
+ ei(z1 +z2 ) − ei(z1 −z2 ) + ei(−z1 +z2 ) − e−i(z1 +z2 )
ei(z1 +z2 ) − e−i(z1 +z2 )
1 i(z1 +z2 )
=
2e
− 2e−i(z1 +z2 ) =
4i
2i
= sin(z1 + z2 )
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Some Proofs Actually Are Simpler Now
sin(z1 ) cos(z2 ) + cos(z1 ) sin(z2 )
eiz1 − e−iz1 eiz2 + e−iz2 eiz1 + e−iz1 eiz2 − e−iz2
=
+
2i
2
2
2i
1 i(z1 +z2 )
+ ei(z1 −z2 ) − ei(−z1 +z2 ) − e−i(z1 +z2 )
e
=
4i
+ ei(z1 +z2 ) − ei(z1 −z2 ) + ei(−z1 +z2 ) − e−i(z1 +z2 )
ei(z1 +z2 ) − e−i(z1 +z2 )
1 i(z1 +z2 )
=
2e
− 2e−i(z1 +z2 ) =
4i
2i
= sin(z1 + z2 )
This is why many people like to work with the complex definition of
the trigonometric functions.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Other Proofs Stay The Same
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Other Proofs Stay The Same
sin(z + 2π)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Other Proofs Stay The Same
sin(z + 2π) = sin(z) cos(2π) + cos(z) sin(2π)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Other Proofs Stay The Same
sin(z + 2π) = sin(z) cos(2π) + cos(z) sin(2π)
= sin(z)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Other Trigonometric Functions
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Other Trigonometric Functions
1. tan(z) :=
sin(z)
cos(z)
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Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Other Trigonometric Functions
sin(z)
cos(z)
cos(z)
2. cot(z) :=
sin(z)
1. tan(z) :=
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Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Other Trigonometric Functions
sin(z)
cos(z)
cos(z)
2. cot(z) :=
sin(z)
1
3. sec(z) :=
cos(z)
1. tan(z) :=
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Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Other Trigonometric Functions
sin(z)
cos(z)
cos(z)
2. cot(z) :=
sin(z)
1
3. sec(z) :=
cos(z)
1
4. csc(z) :=
sin(z)
1. tan(z) :=
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Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Other Trigonometric Functions
sin(z)
cos(z)
cos(z)
2. cot(z) :=
sin(z)
1
3. sec(z) :=
cos(z)
1
4. csc(z) :=
sin(z)
Note that secant and cosecant are not very common (around the
world).
1. tan(z) :=
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Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
1.
d
sin(z)
dz
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Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
1.
d
d eiz −e−iz
sin(z) =
dz
dz
2i
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
1.
d
d eiz −e−iz ieiz +ie−iz
sin(z) =
=
dz
dz
2i
2i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
1.
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
dz
dz
2i
2i
2
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
1.
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
= cos(z)
dz
dz
2i
2i
2
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
= cos(z)
dz
dz
2i
2i
2
d
cos(z) = − sin(z)
2.
dz
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
= cos(z)
dz
dz
2i
2i
2
d
cos(z) = − sin(z)
2.
dz
1
d
tan(z) =
3.
dz
cos2 (z)
1.
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
= cos(z)
dz
dz
2i
2i
2
d
cos(z) = − sin(z)
2.
dz
1
d
tan(z) =
3.
dz
cos2 (z)
1
d
cot(z) = − 2
4.
dz
sin (z)
1.
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
1.
2.
3.
4.
5.
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
= cos(z)
dz
dz
2i
2i
2
d
cos(z) = − sin(z)
dz
1
d
tan(z) =
dz
cos2 (z)
1
d
cot(z) = − 2
dz
sin (z)
d
sec(z) = sec(z) tan(z)
dz
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
1.
2.
3.
4.
5.
6.
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
= cos(z)
dz
dz
2i
2i
2
d
cos(z) = − sin(z)
dz
1
d
tan(z) =
dz
cos2 (z)
1
d
cot(z) = − 2
dz
sin (z)
d
sec(z) = sec(z) tan(z)
dz
d
csc(z) = − csc(z) cot(z)
dz
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
The Derivatives
d
d eiz −e−iz ieiz +ie−iz eiz +e−iz
sin(z) =
=
=
= cos(z)
dz
dz
2i
2i
2
d
cos(z) = − sin(z)
2.
dz
1
d
tan(z) =
3.
dz
cos2 (z)
1
d
cot(z) = − 2
4.
dz
sin (z)
d
5.
sec(z) = sec(z) tan(z)
dz
d
6.
csc(z) = − csc(z) cot(z)
dz
Note that secant and cosecant are not very common (around the
world).
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition.
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
Bernd Schröder
Trigonometric and Hyperbolic Functions
ez + e−z
2
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
sin(iz)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
sin(iz) =
eiiz − e−iiz
2i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
sin(iz) =
eiiz − e−iiz e−z − ez
=
2i
2i
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
sin(iz) =
eiiz − e−iiz e−z − ez
ez − e−z
=
= ii
2i
2i
2i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
sin(iz) =
eiiz − e−iiz e−z − ez
ez − e−z
=
= ii
= i sinh(z)
2i
2i
2i
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Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
sin(iz) =
cos(iz)
eiiz − e−iiz e−z − ez
ez − e−z
=
= ii
= i sinh(z)
2i
2i
2i
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Definition. For any complex number z we define
cosh(z) =
ez + e−z
2
sinh(z) =
ez − e−z
.
2
and
Note.
eiiz − e−iiz e−z − ez
ez − e−z
=
= ii
= i sinh(z)
2i
2i
2i
cos(iz) = cosh(z)
sin(iz) =
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection Between Sine and Hyperbolic Sine
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
=
sin(x) cos(iy) + sin(iy) cos(x) sin(x + iy)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
=
=
sin(x) cos(iy) + sin(iy) cos(x) sin(x + iy)
sin(x) cosh(y) + i sinh(y) cos(x)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
sin(x) cos(iy) + sin(iy) cos(x) sin(x + iy)
= sin(x) cosh(y) + i sinh(y) cos(x) ×
× sin(x) cosh(y) − i sinh(y) cos(x)
=
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
sin(x) cos(iy) + sin(iy) cos(x) sin(x + iy)
= sin(x) cosh(y) + i sinh(y) cos(x) ×
× sin(x) cosh(y) − i sinh(y) cos(x)
=
= sin2 (x) cosh2 (y) + sinh2 (y) cos2 (x)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
sin(x) cos(iy) + sin(iy) cos(x) sin(x + iy)
= sin(x) cosh(y) + i sinh(y) cos(x) ×
× sin(x) cosh(y) − i sinh(y) cos(x)
=
= sin2 (x) cosh2 (y) + sinh2 (y) cos2 (x)
+ sinh2 (y) sin2 (x) − sinh2 (y) sin2 (x)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
sin(x) cos(iy) + sin(iy) cos(x) sin(x + iy)
= sin(x) cosh(y) + i sinh(y) cos(x) ×
× sin(x) cosh(y) − i sinh(y) cos(x)
=
= sin2 (x) cosh2 (y) + sinh2 (y) cos2 (x)
+ sinh2 (y) sin2 (x) − sinh2 (y) sin2 (x)
= sin2 (x) cosh2 (y) − sinh2 (y) + sinh2 (y) cos2 (x) + sin2 (x)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Another Connection
Between Sine and Hyperbolic Sine
2
| sin(z)|
= sin(x + iy)sin(x + iy)
sin(x) cos(iy) + sin(iy) cos(x) sin(x + iy)
= sin(x) cosh(y) + i sinh(y) cos(x) ×
× sin(x) cosh(y) − i sinh(y) cos(x)
=
= sin2 (x) cosh2 (y) + sinh2 (y) cos2 (x)
+ sinh2 (y) sin2 (x) − sinh2 (y) sin2 (x)
= sin2 (x) cosh2 (y) − sinh2 (y) + sinh2 (y) cos2 (x) + sin2 (x)
= sin2 (x) + sinh2 (y)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof.
Bernd Schröder
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof. The only solutions of
2
0 = sin(z)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof. The only solutions of
2 2
0 = sin(z) = sin(x + iy)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof. The only solutions of
2 2
0 = sin(z) = sin(x + iy) = sin2 (x) + sinh2 (y)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof. The only solutions of
2 2
0 = sin(z) = sin(x + iy) = sin2 (x) + sinh2 (y)
are y = 0
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof. The only solutions of
2 2
0 = sin(z) = sin(x + iy) = sin2 (x) + sinh2 (y)
are y = 0 and x = nπ.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof. The only solutions of
2 2
0 = sin(z) = sin(x + iy) = sin2 (x) + sinh2 (y)
are y = 0 and x = nπ. So z = nπ where n is an integer are the zeros of
the sine function.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex sine function are the
numbers nπ where n is an integer.
Proof. The only solutions of
2 2
0 = sin(z) = sin(x + iy) = sin2 (x) + sinh2 (y)
are y = 0 and x = nπ. So z = nπ where n is an integer are the zeros of
the sine function.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
1.
d
sinh(z) = cosh(z)
dz
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
2.
dz
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
2.
dz
3. sinh(z1 + z2 ) = sinh(z1 ) cosh(z2 ) + cosh(z1 ) sinh(z2 )
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
2.
dz
3. sinh(z1 + z2 ) = sinh(z1 ) cosh(z2 ) + cosh(z1 ) sinh(z2 )
4. cosh(z1 + z2 ) = cosh(z1 ) cosh(z2 ) + sinh(z1 ) sinh(z2 )
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
1.
2.
3.
4.
5.
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
dz
sinh(z1 + z2 ) = sinh(z1 ) cosh(z2 ) + cosh(z1 ) sinh(z2 )
cosh(z1 + z2 ) = cosh(z1 ) cosh(z2 ) + sinh(z1 ) sinh(z2 )
cosh2 (z) − sinh2 (z) = 1
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
1.
2.
3.
4.
5.
6.
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
dz
sinh(z1 + z2 ) = sinh(z1 ) cosh(z2 ) + cosh(z1 ) sinh(z2 )
cosh(z1 + z2 ) = cosh(z1 ) cosh(z2 ) + sinh(z1 ) sinh(z2 )
cosh2 (z) − sinh2 (z) = 1
sinh(z + 2πi) = sinh(z)
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
1.
2.
3.
4.
5.
6.
7.
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
dz
sinh(z1 + z2 ) = sinh(z1 ) cosh(z2 ) + cosh(z1 ) sinh(z2 )
cosh(z1 + z2 ) = cosh(z1 ) cosh(z2 ) + sinh(z1 ) sinh(z2 )
cosh2 (z) − sinh2 (z) = 1
sinh(z + 2πi) = sinh(z)
cosh(z + 2πi) = cosh(z)
Bernd Schröder
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
2.
dz
3. sinh(z1 + z2 ) = sinh(z1 ) cosh(z2 ) + cosh(z1 ) sinh(z2 )
4. cosh(z1 + z2 ) = cosh(z1 ) cosh(z2 ) + sinh(z1 ) sinh(z2 )
5. cosh2 (z) − sinh2 (z) = 1
6. sinh(z + 2πi) = sinh(z)
7. cosh(z + 2πi) = cosh(z)
... and more.
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
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Inverse Trigonometric and Hyperbolic Functions
Identities for Hyperbolic Functions
d
sinh(z) = cosh(z)
dz
d
cosh(z) = sinh(z)
2.
dz
3. sinh(z1 + z2 ) = sinh(z1 ) cosh(z2 ) + cosh(z1 ) sinh(z2 )
4. cosh(z1 + z2 ) = cosh(z1 ) cosh(z2 ) + sinh(z1 ) sinh(z2 )
5. cosh2 (z) − sinh2 (z) = 1
6. sinh(z + 2πi) = sinh(z)
7. cosh(z + 2πi) = cosh(z)
... and more. And they can all be verified straight from the definition.
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex hyperbolic sine function are
the numbers nπi, where n is an integer.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex hyperbolic sine function are
the numbers nπi, where n is an integer.
Proof.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex hyperbolic sine function are
the numbers nπi, where n is an integer.
Proof. sinh(z) = −i sin(iz)
Bernd Schröder
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Trigonometric Functions
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Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex hyperbolic sine function are
the numbers nπi, where n is an integer.
Proof. sinh(z) = −i sin(iz) is equal to zero where sin(iz) is equal to
zero.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex hyperbolic sine function are
the numbers nπi, where n is an integer.
Proof. sinh(z) = −i sin(iz) is equal to zero where sin(iz) is equal to
zero. Hence the zeros of sinh(z) are at z = nπi, where n is an integer.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. The only zeros of the complex hyperbolic sine function are
the numbers nπi, where n is an integer.
Proof. sinh(z) = −i sin(iz) is equal to zero where sin(iz) is equal to
zero. Hence the zeros of sinh(z) are at z = nπi, where n is an integer.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
More Hyperbolic Functions
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
More Hyperbolic Functions
1. tanh(z) :=
sinh(z)
cosh(z)
Bernd Schröder
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
More Hyperbolic Functions
sinh(z)
cosh(z)
cosh(z)
2. coth(z) :=
sinh(z)
1. tanh(z) :=
Bernd Schröder
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More Hyperbolic Functions
sinh(z)
cosh(z)
cosh(z)
2. coth(z) :=
sinh(z)
1
3. sech(z) :=
cosh(z)
1. tanh(z) :=
Bernd Schröder
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Trigonometric Functions
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Inverse Trigonometric and Hyperbolic Functions
More Hyperbolic Functions
sinh(z)
cosh(z)
cosh(z)
2. coth(z) :=
sinh(z)
1
3. sech(z) :=
cosh(z)
1
4. csch(z) :=
sinh(z)
1. tanh(z) :=
Bernd Schröder
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Inverse Trigonometric and Hyperbolic Functions
More Hyperbolic Functions
sinh(z)
cosh(z)
cosh(z)
2. coth(z) :=
sinh(z)
1
3. sech(z) :=
cosh(z)
1
4. csch(z) :=
sinh(z)
Note that hyperbolic secant and cosecant are not very common
(around the world) either.
1. tanh(z) :=
Bernd Schröder
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Inverse Trigonometric and Hyperbolic Functions
Remaining Derivatives
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Remaining Derivatives
1.
d
1
tanh(z) =
dz
cosh2 (z)
Bernd Schröder
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Inverse Trigonometric and Hyperbolic Functions
Remaining Derivatives
d
1
tanh(z) =
dz
cosh2 (z)
1
d
coth(z) = −
2.
dz
sinh2 (z)
1.
Bernd Schröder
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Inverse Trigonometric and Hyperbolic Functions
Remaining Derivatives
d
1
tanh(z) =
dz
cosh2 (z)
1
d
coth(z) = −
2.
dz
sinh2 (z)
d
3.
sech(z) = −sech(z) tanh(z)
dz
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
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Inverse Trigonometric and Hyperbolic Functions
Remaining Derivatives
d
1
tanh(z) =
dz
cosh2 (z)
1
d
coth(z) = −
2.
dz
sinh2 (z)
d
3.
sech(z) = −sech(z) tanh(z)
dz
d
4.
csch(z) = −csch(z) coth(z)
dz
1.
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Inverse Trigonometric and Hyperbolic Functions
Remaining Derivatives
d
1
tanh(z) =
dz
cosh2 (z)
1
d
coth(z) = −
2.
dz
sinh2 (z)
d
3.
sech(z) = −sech(z) tanh(z)
dz
d
4.
csch(z) = −csch(z) coth(z)
dz
Note that hyperbolic secant and cosecant are not very common
(around the world) either.
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem. For all complex numbers z we have
1
2 2
arccos(z) = −i log z + i 1 − z
Bernd Schröder
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Trigonometric Functions
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Inverse Trigonometric and Hyperbolic Functions
Theorem. For all complex numbers z we have
1
2 2
arccos(z) = −i log z + i 1 − z
where the right side is a multivalued function.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Proof.
Bernd Schröder
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Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
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Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
Bernd Schröder
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Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
2
Bernd Schröder
Trigonometric and Hyperbolic Functions
= z
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Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
= z
2
eiw − 2z + e−iw = 0
Bernd Schröder
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Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
= z
2
eiw − 2z + e−iw = 0
2
eiw − 2zeiw + 1 = 0
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
= z
2
eiw − 2z + e−iw = 0
2
eiw − 2zeiw + 1 = 0
iw
e
Bernd Schröder
Trigonometric and Hyperbolic Functions
=
√
2z ± 4z2 − 4
2
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Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
= z
2
eiw − 2z + e−iw = 0
2
eiw − 2zeiw + 1 = 0
iw
e
Bernd Schröder
Trigonometric and Hyperbolic Functions
√
2z ± 4z2 − 4
=
p2
= z ± z2 − 1
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
= z
2
eiw − 2z + e−iw = 0
2
eiw − 2zeiw + 1 = 0
√
2z ± 4z2 − 4
e
=
p2
= z ± z2 − 1
p
1
2
w =
log z ± z − 1
i
iw
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
= z
2
eiw − 2z + e−iw = 0
2
eiw − 2zeiw + 1 = 0
iw
e
=
=
w =
=
Bernd Schröder
Trigonometric and Hyperbolic Functions
√
2z ± 4z2 − 4
p2
z ± z2 − 1
p
1
2
log z ± z − 1
i
p
−i log z ± i 1 − z2
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Proof.
w = arccos(z)
cos(w) = z
eiw + e−iw
= z
2
eiw − 2z + e−iw = 0
2
eiw − 2zeiw + 1 = 0
iw
e
=
=
w =
=
Bernd Schröder
Trigonometric and Hyperbolic Functions
√
2z ± 4z2 − 4
p2
z ± z2 − 1
p
1
2
log z ± z − 1
i
p
−i log z ± i 1 − z2
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Similarly We Can Derive ...
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Similarly We Can Derive
...
1. arcsin(z) = −i log iz + 1 − z
Bernd Schröder
Trigonometric and Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
2
12
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Similarly We Can Derive
...
1. arcsin(z) = −i log iz + 1 − z
i
i+z
2. arctan(z) = log
2
i−z
Bernd Schröder
Trigonometric and Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
2
12
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Similarly We Can Derive
...
Inverse Trigonometric and Hyperbolic Functions
2
12
1. arcsin(z) = −i log iz + 1 − z
i
i+z
2. arctan(z) = log
2 i−z
1
2 2
3. arsinh(z) = log z + 1 + z
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Similarly We Can Derive
...
Inverse Trigonometric and Hyperbolic Functions
2
12
1. arcsin(z) = −i log iz + 1 − z
i
i+z
2. arctan(z) = log
2 i−z
1
2 2
3. arsinh(z) = log z + 1 + z
21
2
4. arcosh(z) = log z + z − 1
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Similarly We Can Derive
...
Inverse Trigonometric and Hyperbolic Functions
2
12
1. arcsin(z) = −i log iz + 1 − z
i
i+z
2. arctan(z) = log
2 i−z
1
2 2
3. arsinh(z) = log z + 1 + z
21
2
4. arcosh(z) = log z + z − 1
1
1+z
5. artanh(z) = log
2
1−z
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Theorem.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Theorem.
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1
dz
(1 − z2 ) 2
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Proof.
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Proof.
d
arcsin(z)
dz
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Proof.
d
arcsin(z) =
dz
Bernd Schröder
Trigonometric and Hyperbolic Functions
1
d
2 2
−i log iz + 1 − z
dz
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Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Proof.
d
arcsin(z) =
dz
1
d
2 2
−i log iz + 1 − z
dz
= −i
1
1
iz + (1 − z2 ) 2
Bernd Schröder
Trigonometric and Hyperbolic Functions
!
1
1
i+
(−2z)
2 (1 − z2 ) 12
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Proof.
d
arcsin(z) =
dz
1
d
2 2
−i log iz + 1 − z
dz
!
1
1
= −i
i+
(−2z)
1
2 (1 − z2 ) 12
iz + (1 − z2 ) 2


1
i 1 − z2 2 − z
−i


=
1
1
iz + (1 − z2 ) 2
(1 − z2 ) 2
1
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Proof.
d
arcsin(z) =
dz
1
d
2 2
−i log iz + 1 − z
dz
!
1
1
= −i
i+
(−2z)
1
2 (1 − z2 ) 12
iz + (1 − z2 ) 2


1
i 1 − z2 2 − z
−i


=
1
1
iz + (1 − z2 ) 2
(1 − z2 ) 2
1
=
1
1
(1 − z2 ) 2
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
d
1
arcsin(z) =
1 where the right side is
dz
(1 − z2 ) 2
multivalued again.
Theorem.
Proof.
d
arcsin(z) =
dz
1
d
2 2
−i log iz + 1 − z
dz
!
1
1
= −i
i+
(−2z)
1
2 (1 − z2 ) 12
iz + (1 − z2 ) 2


1
i 1 − z2 2 − z
−i


=
1
1
iz + (1 − z2 ) 2
(1 − z2 ) 2
1
=
1
1
(1 − z2 ) 2
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Similarly ...
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Similarly ...
1.
d
1
arccos(z) = −
1
dz
(1 − z2 ) 2
Bernd Schröder
Trigonometric and Hyperbolic Functions
logo1
Louisiana Tech University, College of Engineering and Science
Trigonometric Functions
Hyperbolic Functions
Inverse Trigonometric and Hyperbolic Functions
Similarly ...
d
1
arccos(z) = −
1
dz
(1 − z2 ) 2
1
d
arctan(z) =
2.
dz
1 + z2
1.
Bernd Schröder
Trigonometric and Hyperbolic Functions
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Louisiana Tech University, College of Engineering and Science
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