Trigonometry Identities problem:

Question

Prove the following;

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

Reiny · Answer

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

hhfo · Answer

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