Question

PLEASE HELP ! Simplify the expression sin^2x-1/cos(-x)
answers :
-sin x

cos x

sin x

-cos x

Answer 1

\(\bf {\color{blue}{ sin^2(\theta)+cos^2(\theta)=1\implies sin^2(\theta)-1=-cos^2(\theta)\\ \quad \\ cos(-x)=cos(x)}}\\ \quad \\ \quad \\

\cfrac{sin^2(x)-1}{cos(-x)}\)

what do you think?

Answer 2

i have no clue?

Answer 3

well, why not use those identities? the pythagorean one and the symmetric one

Answer 4

then simplify