# sum of a series

• October 28th 2008, 01:14 PM
riptorn70
sum of a series
I have a problem finding the sum of the series.
It goes something like this:

(nC0)^2 + (nC1))^2 + (nC2))^2 + ... + (nCn)^2

( I believe I have solved a similar problem, that went as so:

nC0 + nC1 + nC2 + ... + nCn and got 2^n )

anyones assistance would be a great help. Thankyou,
riptorn70
• October 28th 2008, 01:31 PM
Opalg
Hint: In the identity $(1+x)^{2n} = (1+x)^n(1+x)^n$, use the binomial expansion to find the coefficient of $x^n$ on both sides.