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The product of the lengths of perpendiculars drawn from any point on the hyperbola $x^2 -2y^2 -2=0$ to its asymptotes is
$\frac{1}{2}$
$\frac{2}{3}$
$\frac{3}{2}$
$20$
Solution
Given $\frac{x^{2}}{2}-\frac{y^{2}}{1}=1$
Here, $a^{2}=2, \quad b^{2}=1$
Equation of asymptotes to the given hyperbola is
$\frac{x}{{\sqrt 2 }} – \frac{y}{1} = 0$ and ${\rm{ }}\frac{x}{{\sqrt 2 }} + \frac{y}{1} = 0$
Let $P(\sqrt{2} \sec \theta, \tan \theta)$ be any point, then product of length of perpendicular
${=\frac{\left[\frac{\sqrt{2} \sec \theta}{\sqrt{2}}-\frac{\tan \theta}{1}\right]\left[\frac{\sqrt{2} \sec \theta}{\sqrt{2}}+\frac{\tan \theta}{1}\right]}{\sqrt{\frac{1}{2}+\frac{1}{1}} \sqrt{\frac{1}{2}+\frac{1}{1}}}} $
${=\frac{\sec ^{2} \theta-\tan ^{2} \theta}{\frac{3}{2}}=\frac{2}{3}}$