Question

At how many points between the interval $\left(-\infty, \infty\right)$ is the function $f (x) = sin\, x$ is not differentiable.

• A. $0$
• B. $7$
• C. $9$
• D. $3$

Answer 1

Answer: (A)

$0$

Answer 2

The function $f (x) = sin \,x$is differentiable for all $x\,\in\,R.$ Therefore the number of pointsin the interval $\left(-\infty, \infty\right)$ where the function is not differentiable are zero.