Answer
a) $\frac{\pi}{2}$
b) $0$
c) $-\frac{\pi}{6}$
Work Step by Step
a) First, we look at the interval of the inverse of cosine which is $0\lt x\lt \pi$. Then, we must find what angle will give a value of $0$ in that interval. The answer is $\frac{\pi}{2}$
b) First, we look at the interval of the inverse of sine which is $-\frac{\pi}{2}\lt x\lt\frac{\pi}{2}$. Then, we must find what angle will give a slope of $0$ in that interval. The answer is $0$
c) First, we look at the interval of the inverse of sine which is $-\frac{\pi}{2}\lt x\lt\frac{\pi}{2}$. Then, we must find what angle will give a slope of $-1/2$ in that interval. The answer is $-\frac{\pi}{6}$
