Solve the equation for $x$: $\sin^{-1} \left( \frac{5}{x} \right) + \sin^{-1} \left( \frac{12}{x} \right) = \frac{\pi}{2} \quad (x \neq 0)$.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → $x = 13$ ##
Given equation can be written as:
$\sin^{-1} \left( \frac{12}{x} \right) = \frac{\pi}{2} - \sin^{-1} \left( \frac{5}{x} \right)$
$\Rightarrow \sin^{-1} \left( \frac{12}{x} \right) = \cos^{-1} \left( \frac{5}{x} \right)$
$∴\sin^{-1} \left( \frac{12}{x} \right) = \sin^{-1} \left( \frac{\sqrt{x^2 - 25}}{x} \right)$
$\Rightarrow \frac{12}{x} = \frac{\sqrt{x^2 - 25}}{x}$
$\Rightarrow x^2 - 25 = 144$
$\Rightarrow x = \pm 13$
Since $x = -13$ does not satisfy the given equation,
$∴$ Required solution is $x = 13$.