Coefficient of `x^15` in `(1+ x + x^3+ x^4)^n` is

Find the coefficient of x^9 in (1 +3x +3x^2+x^3)^15 .

The coefficient of x^(-17) in (x^4 - (1)/(x^3))^15 is

The coefficient of x^(-17) in (x^4 - (1)/(x^3))^15 is

If | x| lt 1, then the coefficient of x ^(n) in (1 + 2x + 3x ^(2)+ 4x ^(3) +...) ^(1//2), is :

The coefficient of x^(-n) in (1+x)^n (1+(1)/(x))^n is

If n is a positive integer and the coefficient of x^10 in the expansion of (1 + x)^15 is equal to the coefficient of x^5 in the expansion of (1-x)^(-n) then n =

The coefficient of x^(-6) in (x^4-(1)/(x^ 2))^15 is

If sum of the coefficients in the expansion of (x+1/x)^(n) is 128, then coefficient of x in the expansion of (x+1/x)^(n) is