Differential Equations Question 138

Question: The differential equation for which $ {{\sin }^{-1}}x+{{\sin }^{-1}}y=c $ is given by

[Karnataka CET 2003]

Options:

A) $ \sqrt{1-x^{2}}dx+\sqrt{1-y^{2}}dy=0 $

B) $ \sqrt{1-x^{2}}dy+\sqrt{1-y^{2}}dx=0 $

C) $ \sqrt{1-x^{2}}dy-\sqrt{1-y^{2}}dx=0 $

D) $ \sqrt{1-x^{2}}dx-\sqrt{1-y^{2}}dy=0 $

Show Answer

Answer:

Correct Answer: B

Solution:

Given equation is $ {{\sin }^{-1}}x+{{\sin }^{-1}}y=c $

…..(i) On differentiating w.r.t. to x, we get $ \frac{1}{\sqrt{1-x^{2}}}+\frac{1}{\sqrt{1-y^{2}}}\frac{dy}{dx}=0 $

Therefore $ \frac{dy}{dx}=-\frac{\sqrt{1-y^{2}}}{\sqrt{1-x^{2}}} $

Therefore $ \sqrt{1-x^{2}}dy+\sqrt{1-y^{2}}dx=0 $ .