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Black Book Advanced Problems in MathematicsMathematicsContinuity and Differentiability

Let f(x) = |2x - 9| + |2x| + |2x + 9| . Which of the following are true ?

Options

  1. Af(x) is not differentiable at x = 9 2
  2. Bf(x) is not differentiable at x = -9 2
  3. Cf(x) is not differentiable at x = 0
  4. Df(x) is differentiable at x = -9 2 , 0, 9 2

Correct answer

A. f(x) is not differentiable at x = 9 2

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