Pre-Calculus
January 17, 2012
5.4 Sum and Difference Formulas
Use your graphing calculator to verify which is true…
OR
Sum and Difference Identities
The proofs for these identities are found in Appendix C in your textbook.
Pre-Calculus
January 17, 2012
Use the formulas to determine the EXACT values of the following expressions (NO Calculator!)
1. sin(450 + 300) =
2. sin450 + sin300 =
3. cos(1200 - 450) =
4. cos1200 - cos 450) =
Pre-Calculus
January 17, 2012
5.
6. sin1650 =
7. tan150 =
8.
Pre-Calculus
January 17, 2012
Write the expression as the sine, cosine, or tangent of one angle measure.
9. sin 1100 cos 800 + cos 1100 sin 800 =
10.
tan 1520 - tan 470
1 + tan 1520 tan470
11. Find the exact value of the trig function, cos (x + y) given that sin x = 5/13 and cos y = -3/5. Both x
and y are in Quadrant II.
Pre-Calculus
January 17, 2012
Day 2: Using Sum and Difference Identities
Ex 1: Write the trigonometric expression as an algebraic expression.
cos(arcsin x - arctan 2x)
tan(sin-1√x + cos-13x)
Pre-Calculus
January 17, 2012
Example 2: Find the solutions of the equation in the interval [0, 2π). Use the calculator to verify your results.
a.)
b.)