Differential Equations Question 194

Question: The solution of the differential equation $ x\frac{dy}{dx}+y=x^{2}+3x+2 $ is

Options:

A) $ xy=\frac{x^{3}}{3}+\frac{3}{2}x^{2}+2x+c $

B) $ xy=\frac{x^{4}}{4}+x^{3}+x^{2}+c $

C) $ xy=\frac{x^{4}}{4}+\frac{x^{3}}{3}+x^{2}+c $

D) $ xy=\frac{x^{4}}{4}+x^{3}+x^{2}+cx $

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Answer:

Correct Answer: A

Solution:

$ x\frac{dy}{dx}+y=x^{2}+3x+2 $

Therefore $ \frac{dy}{dx}+\frac{y}{x}=x+3+\frac{2}{x} $

Here $ P=\frac{1}{x},\ Q=x+3+\frac{2}{x} $ , therefore I.F. $ \frac{dy}{dx}=-1 $

Now solve it.