Question

Let S be the set of all points in $( - \pi , \pi)$ at which the function, f(x) = min {sinx, cosx} is not differentiable. Then S is a subset of which of the following?

• A. $\left\{ - \frac{3\pi}{4} , \frac{\pi}{4} , \frac{3\pi}{4} , \frac{\pi}{4}\right\} $
• B. $\left\{ - \frac{3\pi}{4} , \frac{\pi}{2} , \frac{\pi}{2} , \frac{3\pi}{4}\right\} $
• C. $\left\{ - \frac{\pi}{2} , \frac{\pi}{4} , \frac{\pi}{4} , \frac{\pi}{2}\right\} $
• D. $\left\{ - \frac{\pi}{4} ,0, \frac{\pi}{4}\right\} $

Answer 1

Answer: (A)

Correct answer is (a) $\left\{ - \frac{3\pi}{4} , \frac{\pi}{4} , \frac{3\pi}{4} , \frac{\pi}{4}\right\} $