Section 7.2: Verifying Trigonometric Identities
November 30, 2015
7-2: Verifying Trigonometric Identities
*Transform one side of the equation until it is the same
as the other side
*Changing only one sides eliminates many possible errors
* you can change either side,
however, I think it is easiest to
change the more complex side
Verify.
1.
1 + tan2θ = sec2θ
1 + sin2θ = sec2θ
cos2θ
This is an example of how we can
verify the Pythagorean Identity
with out using it.
cos2θ + sin2θ sec2θ
=
cos2θ cos2θ
cos2θ + sin2θ = sec2θ
cos2θ
1
= sec2θ
cos2θ
sec2θ
sec2θ =
2. tan2θ - sin2θ = tan2θsin2θ
Pre­Calculus
Section 7.2: Verifying Trigonometric Identities
3. (sinx + cosx)2 = 1 + 2sinxcosx
4. sec2θ - sec2θcos2θ = tan2θ
Pre­Calculus
November 30, 2015
Section 7.2: Verifying Trigonometric Identities
5. sinθ + cosθ = sinθ + cosθ
tanθ cotθ
Pre­Calculus
November 30, 2015