Let $\beta(\mathrm{m}, \mathrm{n})=\int_0^1 x^{\mathrm{m}-1}(1-x)^{\mathrm{n}-1} \mathrm{~d} x, \mathrm{~m},…
Let $\beta(\mathrm{m}, \mathrm{n})=\int_0^1 x^{\mathrm{m}-1}(1-x)^{\mathrm{n}-1} \mathrm{~d} x, \mathrm{~m}, \mathrm{n}>0$. If $\int_0^1\left(1-x^{10}\right)^{20} \mathrm{~d} x=\mathrm{a} \times \beta(\mathrm{b}, \mathrm{c})$, then $100(\mathrm{a}+\mathrm{b}+\mathrm{c})$ equals____
- 1021
- 2120
- 2012
- 1120
Solution
$I=\int_0^1 1 \cdot\left(1-x^{10}\right)^{20} d x$
$x^{10}=t$
$x=t^{1 / 10}$
$d x=\frac{1}{10}(t)^{-9 / 10} d t$
$I=\int_0^1(1-t)^{20} \frac{1}{10}(t)^{-9 / 10} d t$
$I=\frac{1}{10} \int_0^1 t^{-9 / 10}(1-t)^{20} d t$
$a=\frac{1}{10} \quad b=\frac{1}{10} \quad c=21$
Asked in: JEE Main 2024 (05 Apr Shift 2)
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