Question

How do you prove `sin^2theta - tantheta/ cos^2theta - cot^2theta = tan^2theta`?

Answer 1

The identity is false.

Explanation:

The given equation is not true for all `theta`. For example, take `theta = pi/4`. Then we have

`sin^2(theta)-tan(theta)/cos^2(theta)-cot^2(theta) = 1/2 - 2 - 1 = -5/2`

but

`tan^2(theta) = 1`