Rajasthan BoardEnglish MediumSTD 12 ScienceMATHSIntegrals5 Marks
Question
Evaluate $\int_{-1}^1 5 x^4 \sqrt{x^5+1} d x$.
✓
Answer
Let
$I=\int_{-1}^1 5 x^4 \sqrt{x^5+1} d x$
Putting $t=x^5+1 \Rightarrow d t=5 x^4 d x$
So,
$\int 5 x^4 \sqrt{x^5+1} d x =\int \sqrt{t} d t$
$= \frac{2}{3} t^{\frac{3}{2}}=\frac{2}{3}\left(x^5+1\right)^{\frac{3}{2}}$
So, $\int_{-1}^1 5 x^4 \sqrt{x^5+1} d x$
$=\frac{2}{3}\left(\left(x^5+1\right)^{\frac{3}{2}}\right)_{-1}^1$
$=\frac{2}{3}\left(\left(1^5+1\right)^{\frac{3}{2}}-\left((-1)^5+1\right)^{\frac{3}{2}}\right)$
$=\frac{2}{3}\left(2^{\frac{3}{2}}-(0)^{\frac{3}{2}}\right)=\frac{2}{3}(2 \sqrt{2}-0)$
$=\frac{4 \sqrt{2}}{3} \text { }$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.