Question

Trigonometry Identities problem:

Prove the following;

(tan^2x)(cos^2x)
=
(sec^2x - 1)(1-sin^4x) ÷ (1+sin^2x)

Answer 1

remember :
1 + tan^2x = sec^x and 1-sin^2x = cos^2 from the Pythagorean identities, so

RS = tan^2x(1-sin^2x)(1+sin^2)/(1+sin^2x)
= tan^2x(1-sin^2x)
= tan^2x cos^2x
= LS

Answer 2

Okay I was confused about what to do with the power of 4..
Thank You!!