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GeneralHard JEE math MCQ

If $f: \mathbb{R} \rightarrow \mathbb{R}$ is a twice differentiable function such that $f^{\prime \prime}(x)>0$ for all $x \in \mathbb{R}$, and $f\left(\frac{1}{2}\right)=\frac{1}{2}, f(1)=1$, then
  1. A. $f^{\prime}(1) \leq 0$
  2. B. $0<f^{\prime}(1) \leq \frac{1}{2}$
  3. C. $\frac{1}{2}<f^{\prime}(1) \leq 1$
  4. D. $f^{\prime}(1)>1$

Solution

The correct option is **D**.

MATH

hardPYQ Reworded
Question
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If f:RRf: \mathbb{R} \rightarrow \mathbb{R} is a twice differentiable function such that f(x)>0f^{\prime \prime}(x)>0 for all xRx \in \mathbb{R}, and f(12)=12,f(1)=1f\left(\frac{1}{2}\right)=\frac{1}{2}, f(1)=1, then
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