question_answer

Let \[f:\left( -1,\text{ }\,1 \right)\to R\] be a function defined by\[f(x)=max\left\{ -|x|-\sqrt{1-{{x}^{2}}} \right\}\]. If K be the set of all points at which f is not differentiable then K has exactly- [JEE Main Online Paper (Held On 10-Jan-2019 Evening]

A) one element                              

B) three elements

C) five elements     

D)                  two elements

Correct Answer: B

Solution :

\[x\,\,\in \,\,(-1,\,\,1)\]  three points