Q65 / 125 · BITSAT 2017 · Mathematics

Rolle's theorem is not applicable for the function f(x)=|x| in the interval [-1,1] because

  • A
    f'(1) does not exist
  • B
    f'(-1) does not exist
  • C
    f(x) is discontinuous at x=0
  • Correct answer
    D
    f'(0) does not exist

Solution

We have,

f(x)=|x|

Figure

We know that the function is not differentiable at the sharp edges. Hence, fx is not differentiable at x=0.  Therefore, Rolle's theorem is not applicable for the function

f(x)=|x| in [-1,1]

∵ f'(0) does not exist.

Hence, the correct answer is option: 'D'.

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