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Question

Question: Evaluate : \(\int_{0}^{1}x\) (1 – x)<sup>99</sup> dx...

Evaluate : 01x\int_{0}^{1}x (1 – x)99 dx

A

110100\frac{1}{10100}

B

111000\frac{1}{11000}

C

110010\frac{1}{10010}

D

None

Answer

110100\frac{1}{10100}

Explanation

Solution

Let I = 01x\int_{0}^{1}x (1 – x)99 dx

= 01(1x)\int_{0}^{1}{(1 - x)} (1 – (1 – x))99 dx (By Prop. IV)

= 01(1x)\int_{0}^{1}{(1 - x)} x99 dx

= 01(x99x100)\int_{0}^{1}{(x^{99} - x^{100})}dx

=  x100100x10110101\left. \ \frac{x^{100}}{100} - \frac{x^{101}}{101} \right|_{0}^{1}

= 1100\frac{1}{100}1101\frac{1}{101}

= 110100\frac{1}{10100}.