If A and B are coefficients of xn in the expansions of (1+x)2n and (1+x)2n−1respectively, then
A=B
A=2B
2A=B
none of these
We know that coefficient of xr in the expansion of (1+x)m is mCr.Thus, A=2nCn and B=2n−1Cn We have AB= 2nCn 2n−1Cn=(2n)!n!n!(n!)(n−1)!(2n−1)!=2nn=2⇒ A=2B