JEE Previous Year Question

Let f be any continuous function on [0,2] and twice differentiable on (0,2). If f(0)=0,f(a)=1 and f(b)=2, then

Topic: JEE PYQ

Answer: B. Full step-by-step solution below.

  1. Afor all
  2. B for some
  3. Cfor some
  4. Dfor all

Correct answer: B

Solution

(b)
f(0) = 0 f(a) = 1 and f(b) = 2
Let h(x) = f(x) – x has three roots
By Rolle’s theorem h′(x) = f ′(x) – 1 has at least two roots
h′′(x) = f ′′(x) = 0 has at least one roots

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