Question

Which of the following is an identity?

Answer 1

d

Answer 2

haha thank you. That's what I thought it was, but I just wanted to make sure :)

Answer 3

it's actually A \[1=\sin^2x \cot^2x+\cos^2x \tan^2x\\=\sin^2x(\cos^2x/\sin^2x)+\cos^2x(\sin^2x/\cos^2x)\\=\cos^2x+\sin^2x\\=1\\=\rm LHS\]