Use the fundamental identities to simplify the expression. Please, someone, help me? 1 − cos2 x / sec2 x − 1

1 Answer
Jun 13, 2018

= cos^2 x

Explanation:

f(x) = (1- cos^2 x)/(sec^2 x - 1)
Note that:
1 - cos^2 x = sin^2 x
sec^2 x - 1 = 1/cos^2 x - 1 = (1 - cos^2 x)/(cos^2 x)
= sin^2 x/(cos^2 x)
Hence,
f(x) = (sin^2 x)/(sin^2 x/cos^2 x) = cos^2 x