Answer:
See below
Step-by-step explanation:
Verify the expression:
((1-tan^2(x))/(sec^2(x))=cos(2x)
-----------------------
- (1-tan^2(x))/(sec^2(x) =
- (1-tan^2(x))/(1/cos^2(x) =
- (1-tan^2(x))*cos^2(x) =
- cos^2(x) - sin^2(x) =
- cos^2(x) - (1 - cos^2(x)) =
- 2cos^2(x) - 1 =
- cos(2x)
Done
