Question
Integrate the function w.r.t. x: $\frac{\tan ^{4} \sqrt{x} \sec ^{2} \sqrt{x}}{\sqrt{x}}$

Answer

Derivative of $\sqrt{x}$ is $\frac{1}{2} x^{-\frac{1}{2}}=\frac{1}{2 \sqrt{x}}$.
Thus, we use the substitution $\sqrt{x}=t$ so that $\frac{1}{2 \sqrt{x}} d x=d t$ giving dx = 2t dt.
Thus, $\int \frac{\tan ^{4} \sqrt{x} \sec ^{2} \sqrt{x}}{\sqrt{x}} d x$ = $\int \frac{2 t \tan ^{4} t \sec ^{2} t d t}{t}$ = $2 \int \tan ^{4} t \sec ^{2} t d t$ 
Again, we make another substitution tan t = u so that sec2 t dt = du
Therefore, $2 \int \tan ^{4} t \sec ^{2} t d t=2 \int u^{4} d u=2 \frac{u^{5}}{5}+C$ 
= $\frac{2}{5} \tan ^{5} t+C$ (since u = tan t)
= $\frac{2}{5} \tan ^{5} \sqrt{x}+C$ (since $t=\sqrt{x}$)
Hence, $\int \frac{\tan ^{4} \sqrt{x} \sec ^{2} \sqrt{x}}{\sqrt{x}} d x=\frac{2}{5} \tan ^{5} \sqrt{x}+C$ 

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