The middle term in the expansion of (x+1x)2n is:
Since the power is an even number, there will be only one middle term, which is (2n+22)th term or (n+1)th term.
Tn+1=2nCn(x)n(1x)n
= 2nCn
The middle term in the expansion of (x2+1x2+2)n is:
Find the sum of the series nC0nC2+nC1nC3+nC2nC4.....nCn−2nCn