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Question: Answered & Verified by Expert
Let \(f:[1,3] \rightarrow \mathbb{R}\) be continuous and be derivable in \((1,3)\) and \(f^{\prime}(x)=[f(x)]^2+4 \forall x \in(1,3)\). Then
MathematicsApplication of DerivativesWBJEEWBJEE 2023
Options:
  • A \(f(3)-f(1)=5\) holds
  • B \(f(3)-f(1)=5\) does not hold
  • C \(f(3)-f(1)=3\) holds
  • D \(f(3)-f(1)=4\) holds
Solution:
1132 Upvotes Verified Answer
The correct answer is: \(f(3)-f(1)=5\) does not hold
\(\begin{aligned}
& \text { Hint : } f^{\prime}(c)=(f(c))^2+4=\frac{f(3)-f(1)}{2} \\
& \Rightarrow f(3)-f(1)=2(f(c))^2+8
\end{aligned}\)

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