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By using the properties of the definite integral, evaluate the integral: ∫01x(1-x)ndx

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Question

By using the properties of the definite integral, evaluate the integral:

`int_0^1 x(1-x)^n dx`

Sum
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Solution

`int_0^1  (1 - x) [1 - (1 - x)^n] dx        ...[because int_0^a  f(x) dx = int_0^a  f(a - x)  dx]`

Hence,  `I = int_0^1 (1 - x).x^n  dx`

`I = int_0^1  (x^n - x^(n + 1))  dx`

`= ([x^(n + 1)]_0^1)/(n + 1) - ([n^(n + 2)]_0^1)/(n + 2)`

`= 1/(n + 2) - 1/(n + 2)`

`= (n + 2 - n - 1)/((n + 1)(n + 2))`

`= 1/((n + 1)(n + 2))`

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Chapter 7: Integrals - Exercise 7.11 [Page 347]

APPEARS IN

NCERT Mathematics Part 1 and 2 [English] Class 12
Chapter 7 Integrals
Exercise 7.11 | Q 7 | Page 347

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