Limits Continuity And Differentiability Question 54

Question: Let $ f:R\to R $ be a function defined by $ f(x)=min{x+1,| x |+1} $ , Then which of the following is true?

Options:

A) $ f(x) $ is differentiable everywhere

B) $ f(x) $ is not differentiable at x = 0

C) $ f(x)\ge 1 $ for all $ x\in R $

D) $ f(x) $ is not differentiable at $ x=1 $

Show Answer

Answer:

Correct Answer: A

Solution:

$ f(x)=\min {x+1,| x |+1} $

$ \Rightarrow f(x)=x+1\forall x\in R $

Hence, $ f(x) $ is differentiable everywhere for all $ x\in R $ .