Question

simplify: sec^2x (cot^2x - cos^2x)
(sec^2x)(cot^2x) - (sec^2x)(cos^2x)
cot^2x - cos^2x
(csc^2x-1) - (1-sin^2x)
I don't know how to proceed from here??

Answer 1

try converting of
sec = 1/cos
cot = cos/sin

Answer 2

so, it can be