Sum of two middle terms in the expansion of (1+x)2n−1 is
2n−1Cn−1
2n−1Cn
2nCn
2nCn+1n
Two middle terms in the expansion of (1+x)2n−1
are 2n−1+12 th and 2n−1+12+1 th terms, that is, nth and (n+1)th terms
Coefficients of the middle terms in the expansion of
(1+x)2n−1 are 2n−1Cn−1 and 2n−1Cn and their
Sum =2n−1Cn−1 +2n−1Cn=2nCn