The coefficient of `x^2y^3` in the expansion of `(1-x+y)^(20)` is `(20 !)/(213 !)` b. `-(20 !)/(213 !)` c. `(20 !)/(15!2!3!)` d. none of these

The coefficient of x^(8)y^(12) in the expansion of (2x+3y)^(20) is

The coefficient of x^(n) in the expansion of (1 - 9x + 20x^(2))^(-1) is

Find the constant term in the expansion of (sqrt(x) -2/x^(2))^(20)

The sum of 20 terms of the series whose rth term s given by k T(n)=(-1)^n(n^2+n+1)/(n !) is (20)/(19 !) b. (21)/(20 !)-1 c. (21)/(20 !) d. none of these

The coefficient of x^(19) in the polynomial (x-1)(x-2)(x-2^2).......(x-2^(19)) is 2^(20)-2^(19) b. 1-2^(20) c. 2^(20) d. none of these

Find the coefficient of x^(20) in (x^2+2+1/(x^2))^(-5)(1+x^2)^(40)dot

If the sum of the coefficients in the expansion of (q+r)^(20)(1+(p-2)x)^(20) is equal to square of the sum of the coefficients in the expansion of [2rqx-(r+q)*y]^(10) , where p , r , q are positive constants, then

If (1+2x+3x^2)^(10)=a_0+a_1x+a_2x^2++a_(20)x^(20),t h e na_1 equals 10 b. 20 c. 210 d. none of these

The total number not more than 20 digits that are formed by usingd the digits 0, 1, 2, 3, and 4 is a. 5^(20) b. 5^(20)-1 c. 5^(20)+1 d. none of these