Continuity and Differentiability · Class 12 · CBSE · Science Mathematics

The function f(x) = ax + b for x ≤ 1 and f(x) = x² for x > 1 is both continuous and differentiable at x = 1. What are the values of a and b?

Practice question from Continuity and Differentiability (Class 12 · CBSE · Science Mathematics), with the correct answer and a step-by-step solution.

medium · MCQ · Q-107B7C

The function f(x) = ax + b for x ≤ 1 and f(x) = x² for x > 1 is both continuous and differentiable at x = 1. What are the values of a and b?

  1. A.a = 1, b = 0
  2. B.a = 2, b = -1Correct answer
  3. C.a = -2, b = 3
  4. D.a = 2, b = 1

Solution

Continuity at x=1x=1 gives a+b=1a+b=1. Differentiability gives equality of the derivatives: a=2(1)=2a=2(1)=2. Therefore, b=1−a=−1b=1-a=-1.

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