If ak is the coefficient of x^k in the e...

If `a_k` is the coefficient of `x^k` in the expansion of `(1+x+x^2)^n` for `k = 0, 1, 2, ......., 2n` then `a_1+2a_2+3a_3+...+2na_(2n)=`

A

`-a_(0)`

B

`3^(n)`

C

`n*3^(n+1)`

D

`n*3^(n)`

Text Solution

Verified by Experts

The correct Answer is:

D

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