Differential Equations Question 339

Question: The solution of differential equation $ x\frac{dy}{dx}+y=y^{2} $ is

Options:

A) $ y=1+cxy $

B) $ y=\log {cxy} $

C) $ y+1=cxy $

D) $ y=c+xy $

Show Answer

Answer:

Correct Answer: A

Solution:

$ x\frac{dy}{dx}+y=y^{2} $

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

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

Therefore $ [ \frac{1}{y-1}-\frac{1}{y} ]dy=\frac{dx}{x} $

On integrating, we get $ \log (y-1)-\log y=\log x+\log c $

Therefore $ \frac{y-1}{y}=xc $

Therefore $ y=1+cxy $ .