A) \[4n\]
B) \[4n-3\]
C) \[4n+1\]
D) None of these
Correct Answer: A
Solution :
Given term can be written as \[{{(1+x)}^{2}}{{(1-x)}^{-2}}\] \[=(1+2x+{{x}^{2}})[1+2x+3{{x}^{2}}+....+(n-1){{x}^{n-2}}\] \[={{x}^{n}}(n+1+2n+n-1)+....\] Therefore coefficient of \[{{x}^{n}}\] is 4n.You need to login to perform this action.
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