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Find the coefficient of x^5 in (1+2x+3x^...

Find the coefficient of `x^5` in `(1+2x+3x^2...........)^(-3/2)`

A

21

B

25

C

26

D

none of these

Text Solution

Verified by Experts

The correct Answer is:
D
`(1+2x+3x^(2)+"……")^(-3//2) =[(1-x)^(-2)]^(-3//2)`
`= (1-x)^(3)= 1-3x+3x^(2) - x^(3)`
Therefore, coefficientof `x^(5)` is `0`
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  15. If |x|<1, then find the coefficient of x^n in the expansion of (1+x+x^...

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  18. If the expansion in power of x of the function (1)/(( 1 - ax)(1 - b...

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