Find a particular solution of the differential equation $(x+1) \frac{d y}{d x}=2 e^{-y}-1$, given that $y=0$ when $x=0$
$(x+1) \frac{d y}{d x}=2 e^{-y}-1$
$\Rightarrow \frac{d y}{2 e^{-y}-1}=\frac{d x}{x+1}$
$\Rightarrow \frac{e^{y} d y}{2-e^{y}}=\frac{d x}{x+1}$
Integrating both sides, we get:
$\int \frac{e^{y} d y}{2-e^{y}}=\log |x+1|+\log \mathrm{C}$ ...(1)
Let $2-e^{y}=t$.
$\therefore \frac{d}{d y}\left(2-e^{y}\right)=\frac{d t}{d y}$
$\Rightarrow-e^{y}=\frac{d t}{d y}$
$\Rightarrow e^{y} d t=-d t$
Substituting this value in equation (1), we get:
$\int \frac{-d t}{t}=\log |x+1|+\log \mathrm{C}$
$\Rightarrow-\log |t|=\log |\mathrm{C}(x+1)|$
$\Rightarrow-\log \left|2-e^{y}\right|=\log |\mathrm{C}(x+1)|$
$\Rightarrow \frac{1}{2-e^{y}}=\mathrm{C}(x+1)$
$\Rightarrow 2-e^{y}=\frac{1}{\mathrm{C}(x+1)}$ ...(2)
Now, at x = 0 and y = 0, equation (2) becomes:
$\Rightarrow 2-1=\frac{1}{C}$
$\Rightarrow C=1$
Substituting C = 1 in equation (2), we get:
$2-e^{y}=\frac{1}{x+1}$
$\Rightarrow e^{y}=2-\frac{1}{x+1}$
$\Rightarrow e^{y}=\frac{2 x+2-1}{x+1}$
$\Rightarrow e^{y}=\frac{2 x+1}{x+1}$
$\Rightarrow y=\log \left|\frac{2 x+1}{x+1}\right|,(x \neq-1)$
This is the required particular solution of the given differential equation.