Mathematics
gtnurse143
37

simplify the expression sin^2 x-1/ cos(-x) the answer choices are  -sin x  cos x sin x -cos x

+3
(1) Answers
Collegegirl763

[latex]\hbox{using trigonometric identities:} \\ \sin^2x +\cos^2x=1 \\ \sin^2x=1-\cos^2x \\ and \\ \cos (-x)=\cos x \\ \\ \frac{\sin^2x-1}{\cos (-x)}=\frac{1-\cos^2 x-1}{\cos x}=\frac{-\cos^2x}{\cos x}=\boxed{- \cos x} \\ (x \not= \frac{\pi}{2}+n\pi, n \in \mathbb{Z})[/latex]

Add answer