The differential equation $x \frac{d y}{d x}-y=x^2$ has the general solution: |
$y-x^3=2 c x$, where c is a constant. $2 y-x^3=c x$, where c is a constant. $y=x^2+c x$, where c is a constant. $y=-x^2-c x$, where c is a constant. |
$y=x^2+c x$, where c is a constant. |
The correct answer is Option (3) → $y=x^2+c x$, where c is a constant. $x \frac{dy}{dx}-y=x^2⇒\frac{dy}{dx}-\frac{y}{x}=x$ $I.F.:e^{\int-\frac{1}{x}dx}=e^{-\log x}=\frac{1}{x}$ so multiplying eq. by $\frac{1}{x}$ $⇒\frac{1}{x}\frac{dy}{dx}-\frac{y}{x^2}=1$ so $\frac{y}{x}=\int 1dx⇒y=x(x+c)$ $y=x^2+cx$ |