If the coefficients of second, third and fourth terms in the expansion of `(1+x)^n` are in AP then n equals

If the coefficients of 5th, 6th , and 7th terms in the expansion of (1+x)^n are in A.P., then n=

If the coefficients of rth, (r+1)t h ,a n d(r+2)t h terms in the expansion of (1+x)^(14) are in A.P., then r is/are a. 5 b. 11 c. 10 d. 9

If the coefficient of the rth, (r+1)th and (r+2)th terms in the expansion of (1+x)^(n) are in A.P., prove that n^(2) - n(4r +1) + 4r^(2) - 2=0 .

Find the fourth term in the expansion of : (4/7x-y^2)^5 .

For what value of m, the coefficients of (2m + 1)^(th) and (4m+5)^(th) terms in the expansion of (1 + x)^10 are equal ?

If the fourth term in the expansion of (px+1/x)^n is 5/2 , then (n,p)=

The coefficients of the (r-1)^(th) , r^(th) and (r+1)^(th) terms in the expansion of (x + 1)^n are in the ratio 1:3:5. Find n and r.

The middle term in the expansion of (1 + x)^(2n) is :