Sum of two middle terms in the expansion of (1+x)2n−1 is

Two middle terms in the expansion of (1+x)2n−1 are 2n−1+12th and 2n−1+12+1th 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