Mathematics

Problem

Let

h(x)=\dfrac{\sin x}{1+\cos x}

for all

x

such that

\cos x\neq -1

. Which of the following is an equivalent simplified form of

h'(x)

? a)

-\dfrac{1}{1+\cos x}

\dfrac{\cos x}{1+\cos x}

\dfrac{1}{1+\cos x}

\dfrac{1-\cos x}{(1+\cos x)^2}