Trigonometric Identities and
Equations
SECTION 7-2
VERIFYING TRIGONOMETRIC IDENTITIES
Using the basic identities to verify other identities
y Verifying trigonometric identities algebraically
involves transforming one side of the equation into
the same form as the other side by using the basic
trigonometric identities and properties of algebra.
Remember the strategies
y 1. Transform the more complicated side of the
y
y
y
y
equation into the simpler side.
2. Substitute one or more basic trigonometric
identities to simplify expressions.
3. Factor or multiple to simplify expressions.
4. Multiple expressions by an expression equal to 1.
5. Express all trigonometric functions in terms of
sine and cosine.
More examples!
y
Verify that the left side of this expression equals the right side of the
expression.
Finding a numerical value of one trigonometric function of x
y Suppose we are told that cot x/csc x =.6 and we are
asked to find a numerical value of one trigonometric
function of x if the above information holds true.
cos x
cot x
= sin x =
1
csc x
sin x
cos x
Therefore
cos x = .6
HW#2
y Section 7-2
y Pp 434-436
y #15-31 odd, 46, 48, 50