Find the sum of the coefficients in the expansion of `(1+2x+3x^2+ n x^n)^2dot`

If the sum of the coefficients in the expansion of (1 -3x + 10x^2)^(n) is a and the sum of the coefficients in the expansion of (1 - x^(2))^(n) is b , then

Find the coefficient of x^4 in the expansion of (2-x+3x^2)^6dot

Find the sum of all the coefficients in the binomial expansion of (x^2+x-3)^(319)dot

Find the coefficient of x ^(3) in the expansion of (2 -3x)^(7).

If |x|<1, then find the coefficient of x^n in the expansion of (1+x+x^2+x^3+....)^2dot

Find the greatest coefficient in the expansion of (1+2x//3)^(15)dot .

Find the coefficient of x^3 in the expansion of (2-3x)^7 ?

if the sum of coefficients in the expansion of (x-2y+3z)^n is 128, then find the greatest coefficients in the expansion of (1+x)^ndot

Find the coefficient of x^7 in the expansion of (1+3x-2x^3)^(10)dot