JEE Main 2024 — Inverse Trigonometric Functions Question with Solution
JEE Main 2024 (04 Apr Shift 2)
Question
Given that the inverse trigonometric function assumes principal values only. Let , be any two real numbers in such that .
Then, the minimum value of is
Then, the minimum value of is
Choose an option
Show full solutionCorrect option: A
Correct answer
A0
Step-by-step explanation
$\begin{aligned}
& \cos ^{-1} x-\left(\frac{\pi}{2}-\cos ^{-1} y\right)=\alpha \\
& \cos ^{-1} x+\cos ^{-1} y=\frac{\pi}{2}+\alpha \\
& \alpha \in\left[-\frac{\pi}{2}, \pi\right], \frac{\pi}{2}+\alpha \in\left[0, \frac{3 \pi}{2}\right] \\
& \cos ^{-1}\left(x y-\sqrt{1-x^2} \sqrt{1-y^2}\right)=\frac{\pi}{2}+\alpha \\
& x y-\sqrt{1-x^2} \sqrt{1-y^2}=-\sin \alpha \\
& (x y+\sin \alpha)=\left(1-x^2\right)\left(1-y^2\right) \\
& x^2 y^2+2 x y \sin a+\sin ^2 a=1-x^2-y^2+x^2 y^2 \\
& x^2+y^2+2 x y \sin \alpha=1-\sin ^2 \alpha \\
& x^2+y^2+2 x y \sin \alpha=\cos ^2 \alpha
\end{aligned}\cos ^2 \alpha=0$
At
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This is a previous-year question from JEE Main 2024, covering the Inverse Trigonometric Functions 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.