Differential Equations Question 106

Question: The differential equation of the family of curves represented by the equation $ x^{2}y=a $ , is

Options:

A) $ \frac{dy}{dx}+\frac{2y}{x}=0 $

B) $ \frac{dy}{dx}+\frac{2x}{y}=0 $

C) $ \frac{dy}{dx}-\frac{2y}{x}=0 $

D) $ \frac{dy}{dx}-\frac{2x}{y}=0 $

Show Answer

Answer:

Correct Answer: A

Solution:

$ x^{2}y=a $

(On differentiating) $ x^{2}\frac{dy}{dx}+y\frac{d}{dx}(x^{2})=0 $

Therefore $ x^{2}\frac{dy}{dx}+2xy=0 $

Therefore $ \frac{dy}{dx}+\frac{2y}{x}=0 $ .