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Question: Answered & Verified by Expert
Let $f: R \rightarrow R$ be a differentiable function such that $f(a)=0=f(b)$ and $f^{\prime}\left(\right.$ a) $f^{\prime}(b)>0$ for some $a < b$. Then the minimum number of roots of $f^{\prime}(x=0$ in the interval $(a, b)$ is-
MathematicsApplication of DerivativesKVPYKVPY 2010 (SB/SX)
Options:
  • A 3
  • B 2
  • C 1
  • D 0
Solution:
2795 Upvotes Verified Answer
The correct answer is: 2
$f^{\prime}(a), f^{\prime}(b)>0$
so either both are positive or both are negative
$\mathrm{f}(\mathrm{a})=\mathrm{f}(\mathrm{b})=0$


2 roots

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