Question
Integrate the function $\sqrt{x^{2}+4 x+1}$

Answer

Let $I=\int \sqrt{x^{2}+4 x+1} d x$
$=\int \sqrt{\left(x^{2}+4 x+4\right)-3} d x$
$= \int \sqrt{(x+2)^{2}-(\sqrt{3})^{2}} d x$
We know that
$\int \sqrt{(x)^{2}-(a)^{2}} d x$ = $\frac{x}{2} \sqrt{x^{2}+a^{2}}-\frac{a^{2}}{2} \log |x+\sqrt{x^{2}-a^{2}}|+C$
Therefore,
$\Rightarrow \mathrm{I}=\frac{(\mathrm{x}+2)}{2} \sqrt{\mathrm{x}^{2}+4 \mathrm{x}+1}-\frac{3}{2} \log |(\mathrm{x}+2)+\sqrt{\mathrm{x}^{2}+4 \mathrm{x}+1}|+\mathrm{C}$

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