Question
Integrate the function: $\frac{{\cos \sqrt x }}{{\sqrt x }}$

Answer

Let $I = \int {\frac{{\cos \sqrt x }}{{\sqrt x }}dx} $ ...(i)Putting $\sqrt x = t$
$\Rightarrow x = t^2$
$ \Rightarrow \frac{{dx}}{{dt}} = 2t$
$ \Rightarrow $ dx = 2tdt
$\therefore$ From eq. (i), $I = \int {\frac{{\cos t}}{t}2tdt} $
$ = 2\int {\cos t\,dt} $
= 2 sin t + c
$ = 2\sin \sqrt x + 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