Functions Question 479

Question: The function $ f(x)=\max

[(1-x),,(1+x),,2], $ $ x\in (-\infty ,,\infty ), $ is [IIT 1995]

Options:

A) Continuous at all points

B) Differentiable at all points

C) Differentiable at all points except at $ x=1 $ and $ x=-1 $

D) Continuous at all points except at $ x=1 $ and $ x=-1 $ where it is discontinuous

Show Answer

Answer:

Correct Answer: C

Solution:

$ f(x)=\max { (1-x),(1+x),2 },\forall x\in (-,\infty ,,\infty ). $ $ f(x)={ \begin{array}{*{35}{r}} 1+x; & x>1 \\ 2; & -1\le x\le 1 \\ 1-x; & x
\ $ f(x) $ is differentiable at all the points, except at
$ x=1 $ and at $ x=-1 $ …..(ii)