Coefficient of the term independent of x in the expan-sion of (1+x)2nx1−x−2n is :

Coefficient of the term independent of x in the expan-sion of(1+x)2nx1−x−2nor (1+x)2n(1-x)2nx2n = coefficient of x2n in 1−x22n= coefficient of tn in (1−t)2n=2nCn(−1)n