Which of the following functions is non-differentiable?

MATHEMATICS · Single correct · CBSE · Mathematics · Continuity and Differentiability · Continuity and Differentiability

Problem

Which of the following functions is non-differentiable? (a)

f(x)=(e^x-1)\lvert e^{2x}-1\rvert

\mathbb{R}

(b)

f(x)=\frac{x-1}{x^2+1}

\mathbb{R}

(c)

f(x)=\begin{cases}\lvert\lvert x-3\rvert-1\rvert, & x<3\\ \frac{x}{3}[x]-2, & x\geq 3\end{cases}

x=3

where

[\cdot]

represents the greatest integer function (d)

f(x)=3(x-2)^{1/3}+3

\mathbb{R}