Question
Evalute : $\int e^x \frac{1+x}{(2+x)^2} d x$

Answer

$
\begin{aligned}
& \text { Let } I=\int e^x \frac{1+x}{(2+x)^2} d x \\
& =\int e^x\left[\frac{(2+x)-1}{(2+x)^2}\right] d x \\
& =\int e^x\left[\frac{1}{2+x}-\frac{1}{(2+x)^2}\right] d x
\end{aligned}
$
Let $f(x)=\frac{1}{2+x}$
$
\begin{aligned}
& \therefore f^{\prime}(x)=\frac{-1}{(2+x)^2} \\
& \therefore I=\int e^x[f(x)+f \prime(x)] d x \\
& =e^x \cdot f(x)+c \\
& =e^x \cdot \frac{1}{2+x}+c \\
& \therefore I=\frac{e^x}{2+x}+c
\end{aligned}
$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free