JEE Main 2024 — Application of Derivatives Question with Solution
JEE Main 2024 (04 Apr Shift 2)
Question
Let be a real valued function. If and are respectively the minimum and the maximum values of , then is equal to
Choose an option
Show full solutionCorrect option: A
Correct answer
A42
Step-by-step explanation
$\begin{aligned}
& f(x)=3 \sqrt{x-2}+\sqrt{4-x} \\
& x-2 \geq 0 \& 4-x \geq 0 \\
& \therefore x \in[2,4]
\end{aligned}x=2 \sin ^2 \theta+4 \cos ^2 \theta$
$\begin{aligned}
& \therefore \mathrm{f}(\mathrm{x})=3 \sqrt{2}|\cos \theta|+\sqrt{2}|\sin \theta| \\
& \therefore \sqrt{2} \leq 3 \sqrt{2}|\cos \theta|+\sqrt{2}|\sin \theta| \leq \sqrt{9 \times 2+2} \\
& \sqrt{2} \leq 3 \sqrt{2}|\cos \theta|+\sqrt{2}|\sin \theta| \leq \sqrt{20} \\
& \therefore \alpha=\sqrt{2} \quad \beta=\sqrt{20} \\
& \alpha^2+2 \beta^2=2+40=42
\end{aligned}$
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This is a previous-year question from JEE Main 2024, covering the Application of Derivatives chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.