JEE MAIN - Mathematics (2024 - 5th April Evening Shift - No. 11)
Explanation
First, let's rewrite the given integral using the given form of the Beta function. The given integral is:
$$\int_\limits0^1\left(1-x^{10}\right)^{20} \mathrm{~d} x$$
To use the Beta function, let us make a substitution. Let $ x^{10} = t $. Then, $ dx = \frac{1}{10}t^{-\frac{9}{10}} dt $ or $ dx = \frac{1}{10} t^{-\frac{9}{10}} dt $. The limits of integration change as follows: when $ x = 0 $, $ t = 0 $, and when $ x = 1 $, $ t = 1 $.
Substituting these into the integral, we have:
$$\int_\limits0^1 (1 - t)^{20} \cdot \frac{1}{10} t^{-\frac{9}{10}} dt$$
which simplifies to:
$$\frac{1}{10} \int_\limits0^1 (1 - t)^{20} t^{-\frac{9}{10}} dt$$
We recognize this integral as a Beta function $ \beta(m, n) $ where $ m = 1 - \frac{9}{10} = \frac{1}{10} $ and $ n = 20 + 1 = 21 $.
Therefore, we can write this as:
$$\frac{1}{10} \beta \left( \frac{1}{10}, 21 \right)$$
Comparing this to $ a \times \beta(b, c) $, we have $ a = \frac{1}{10} $, $ b = \frac{1}{10} $, and $ c = 21 $.
Now we calculate $ 100(a + b + c) $:
$$100 \left( \frac{1}{10} + \frac{1}{10} + 21 \right) = 100 \left( \frac{1}{10} + \frac{1}{10} + 21 \right) = 100 \left( \frac{1}{5} + 21 \right) = 100 \left( \frac{1}{5} + \frac{105}{5} \right) = 100 \left( \frac{106}{5} \right) = 100 \times 21.2 = 2120$$
So, the answer is Option D, 2120.
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