Solve the equation for $x$: $\sin^{-1} \left( \frac{5}{x} \right) + \sin^{-1} \left( \frac{12}{x} \right) = \frac{\pi}{2} \quad (x \neq 0)$. |
$x = 13$ $x = \pm 13$ $x = 17$ $x = \pm 17$ |
$x = 13$ |
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 $x = 13$. |