`"^(40)C_0` + `"^(40)C_1` + `"^(40)C_2` + …..+`"^(40)C_(19)`+`"^(40)C_(20)` is equal to

The sum S = ""^(20)C_(2) + 2*""^(20)C_(3) + 3 *""^(20)C_(4) + ...+ 19 * ""^(20)C_(20) is equal to

If 20C_(r+1)=^20C_(r-1) , then r is equal to:

C_(0)-C_(1)+C_(2)-C_(3)+ ---+(-1)^(n)""^(n)C_(n) is equal to

The value of sum_(r=0)^(20)r(20-r)(^(20)C_r)^2 is equal to 400^(39)C_(20) b. 400^(40)C_(19) c. 400^(39)C_(19) d. 400^(38)C_(20)

The sum of series .^(20)C_0-^(20)C_1+^(20)C_2-^(20)C_3+....+^(20)C _10 is

If (1 + x)^(n) = C_(0) + C_(1) x +C_(2) x^(2) +…+ C_(n) x^(n) , then the sum C_(0) + (C_(0)+C_(1))+…+(C_(0) +C_(1) +…+C_(n -1)) is equal to

If C_0+C_1+C_2+…………+C_n=256 , then ^(2n)C_2 is equal to:

If (1 + x)^(n) = sum_(r=0)^(n) C_(r) x^(r),(1 + (C_(1))/(C_(0))) (1 + (C_(2))/(C_(1)))...(1 + (C_(n))/(C_(n-1))) is equal to

Rational number 3/40 is equal to :

If (1 + x+ 2x^(2))^(20) = a_(0) + a_(1) x + a_(2) x^(2) + …+ a_(40) x^(40) . The value of a_(0) + a_(2) + a_(4) + …+ a_(38) is