Verified Solution • 2025–26 Session moderate

QJEEM24Madd54: JEE Main 2024 Mathematics - Class 12 JEEM24Madd54 Solution: For , if and , then equals

For α,β,γ≠0\alpha, \beta, \gamma \neq 0 , if sin⁡−1α+sin⁡−1β+sin⁡−1γ=π\sin ^{-1} \alpha+\sin ^{-1} \beta+\sin ^{-1} \gamma=\pi and (α+β+γ)(α−γ+β)=3αβ(\alpha+\beta+\gamma)(\alpha-\gamma+\beta)=3 \alpha \beta , then γ\gamma equals

Multiple Choice Options

  • A 3\sqrt{3}
  • B 32\frac{\sqrt{3}}{2}
  • C 12\frac{1}{\sqrt{2}}
  • D 3−122\frac{\sqrt{3}-1}{2 \sqrt{2}}

Step-by-Step Verified Solution

Let sin⁡−1α=A,sin⁡−1β=B,sin⁡−1γ=C\sin ^{-1} \alpha=A, \sin ^{-1} \beta=B, \sin ^{-1} \gamma=C

amp;A+B+C=πamp;(α+β)2−γ2=3αβamp;α2+β2−γ2=αβamp;α2+β2−γ22αβ=12amp;⇒cos⁡C=12amp;sin⁡C=γamp;cos⁡C=1−γ2=12amp;γ=32\begin{aligned}& \mathrm{A}+\mathrm{B}+\mathrm{C}=\pi \\& (\alpha+\beta)^2-\gamma^2=3 \alpha \beta \\& \alpha^2+\beta^2-\gamma^2=\alpha \beta \\& \frac{\alpha^2+\beta^2-\gamma^2}{2 \alpha \beta}=\frac{1}{2} \\& \Rightarrow \cos \mathrm{C}=\frac{1}{2} \\& \sin \mathrm{C}=\gamma \\& \cos \mathrm{C}=\sqrt{1-\gamma^2}=\frac{1}{2} \\& \gamma=\frac{\sqrt{3}}{2}\end{aligned}

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