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MHT CET · Maths · Inverse Trigonometric Functions

If \(\sin ^{-1}\left(\frac{x}{13}\right)+\operatorname{cosec}^{-1}\left(\frac{13}{12}\right)=\frac{\pi}{2}\), then the value of \(x\) is

  1. A 4
  2. B 12
  3. C 5
  4. D 11
Verified Solution

Answer & Solution

Correct Answer

(C) 5

Step-by-step Solution

Detailed explanation

\(\begin{aligned}
& \sin ^{-1}\left(\frac{x}{13}\right)=\frac{\pi}{2}-\operatorname{cosec}^{-1}\left(\frac{13}{12}\right) \\
& =\sec ^{-1}\left(\frac{13}{12}\right)=\cos ^{-1}\left(\frac{12}{13}\right) \\
& \therefore \quad \sin ^{-1}\left(\frac{x}{13}\right)=\sin ^{-1}\left(\frac{5}{13}\right) \\
& \therefore \quad x=5
\end{aligned}\)