Differential Equations Question 322

Question: The solution of the differential equation $ (1+x^{2})\frac{dy}{dx}=x $ is

Options:

A) $ y={{\tan }^{-1}}x+c $

B) $ y=-{{\tan }^{-1}}x+c $

C) $ y=\frac{1}{2}{\log _{e}}(1+x^{2})+c $

D) $ y=-\frac{1}{2}{\log _{e}}(1+x^{2})+c $

Show Answer

Answer:

Correct Answer: C

Solution:

$ (1+x^{2})\frac{dy}{dx}=x $

Therefore $ dy=\frac{x}{1+x^{2}}dx $

Therefore $ \int{dy}=\int{\frac{x}{1+x^{2}}dx}+c $

Therefore $ y=\frac{1}{2}{\log _{e}}(1+x^{2})+c $ .