Differential Equations Question 318

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

[MP PET 2004]

Options:

A) $ e^{y}=e^{x}+\frac{x^{3}}{3}+c $

B) $ e^{y}=e^{x}+2x+c $

C) $ e^{y}=e^{x}+x^{3}+c $

D) $ y=e^{x}+c $

Show Answer

Answer:

Correct Answer: A

Solution:

$ \frac{dy}{dx}={e^{x-y}}+x^{2}{e^{-y}}={e^{-y}}(e^{x}+x^{2}) $

Therefore $ e^{y}dy=(x^{2}+e^{x})dx $

Now integrating both sides, we get $ e^{y}=\frac{x^{3}}{3}+e^{x}+c $ .