Question

In the expansion of (1+x)n the coefficient of pth and (p+1)th terms are respectively p and q. The p + q =

Answer 1

option b is the correct answer........

first find general tern of (1+x)n

Tr+1 = nCr xr

Tp= T(p-1)+1= nCp-1 xp-1

Cofficient of pth term = P

nCp-1 = P

Tp+1= T(p)+1= nCp xp

Cofficient of (P+1)th term = q

nCp= q

P+q = nCp-1 + nCp

   =n+1Cp