The Solution of differential equation $\frac{{dy}}{{dx}} + \frac{y}{x} = \sin x$ is
The Solution of differential equation $\frac{{dy}}{{dx}} + \frac{y}{x} = \sin x$ is
Official Solution
Given differential equation is
$\frac{{dy}}{{dx}} + y\frac{1}{x} = \sin x$
which is linear differential equation.
Here,
$P = \frac{1}{x}$
and $Q = \sin x$
$\therefore$ ${\rm{IF}} = {e^{\int {\frac{1}{x}} dx}} = {e^{\log x}} = x$
The general Solution is
$y \cdot x = \int x \cdot \sin xdx + C$
……(i)
Take $I = \int x \sin xdx$
$- x\cos x - \int - \cos xdx$
$= - x\cos x + \sin x$
Put the value of $l$ in Eq. (i),
we get
$xy = - x\cos x + \sin x + C$
$\Rightarrow$ $x(y + \cos x) = \sin x + C$
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