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Question: Answered & Verified by Expert
Let \(\cos ^{-1}\left(\frac{y}{b}\right)=\log _e\left(\frac{x}{n}\right)^n\), then \(A y_2+B y_1+C y=0\) is possible for
MathematicsDifferentiationWBJEEWBJEE 2023
Options:
  • A \(\mathrm{A}=2, \mathrm{~B}=\mathrm{x}^2, \mathrm{C}=\mathrm{n}\)
  • B \(A=x^2, B=x, C=n^2\)
  • C \(A=x, B=2 x, C=3 n+1\)
  • D \(A=x^2, B=3 x, C=2 n\)
Solution:
1566 Upvotes Verified Answer
The correct answer is: \(A=x^2, B=x, C=n^2\)
\(\begin{aligned}
& \text { Hint: } \frac{-1}{\sqrt{1-\frac{y^2}{b^2}}} \times \frac{1}{b} y_1=\left(\frac{n}{n \times \frac{x}{n}}\right) \\
& \Rightarrow \frac{-1 y_1}{\sqrt{b^2-y^2}}=\frac{n}{x} \\
& \Rightarrow y_1 x+n \sqrt{b^2-y^2}=0 \\
& \Rightarrow y_1+x y_2+\frac{n}{2 \sqrt{b^2-y^2}} \cdot(-2 y) y_1=0
\end{aligned}\)
\(\begin{aligned} & \Rightarrow y_1+x y_2+\frac{n^2}{x} y=0 \\ & \Rightarrow y_1 x+x^2 y_2+n^2 y=0 \\ & \Rightarrow x^2 y_2+x y_1+n^2 y=0 \\ & A=x^2, B=x, C=n^2\end{aligned}\)

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