`sumsum_(0leqiltjleqn) C(n,i)C(n,j)` is equal to

sum_(0<=i

(1+x)=C_(0)+C_(1)x+….+C_(n)x^(n) then the value of sumsum_(0lerltslen)C_(r)C_(s) is equal to :

(1+x)=C_(0)+C_(1)x+….+C_(n)x^(n) then the value of sumsum_(0lerltslen)C_(r)C_(s) is equal to :

sum_(0<=i

If (1+x)^(n)=C_(0)+C_(1)x+C_(2)x^(2)+….+C_(n)x^(n) , then sumsum_(0lerltslen)(r+s)C_(r)C_(s) is equal to :

If (1+x)^n=C_0+C_1x+C_2x^2+.......+C_n x^n , then show that the sum of the products of the coefficients taken two at a time, represented by sumsum_(0lt=iltjlt=n) "^nc_i "^n c_j is equal to 2^(2n-1)-((2n)!)/ (2(n !)^2)

If (1+x)^n=C_0+C_1x+C_2x^2+.......+C_n x^n , then show that the sum of the products of the coefficients taken two at a time, represented by sumsum_(0lt=iltjlt=n) "^nc_i "^n c_j is equal to 2^(2n-1)-((2n)!)/ (2(n !)^2)

If (1+x)^n=C_0+C_1x+C_2x^2+.......+C_n x^n , then show that the sum of the products of the coefficients taken two at a time, represented by sumsum_(0lt=iltjlt=n) ""^nc_i ""^n c_j is equal to 2^(2n-1)-((2n)!)/ (2(n !)^2)

If (1+x)^(n)=C_(0)+C_(1)x+C_(2)x^(2)+......+C_(n)x^(n) then show that the sum of the products of the coefficients taken two at a time,represented by sum sum_(0<=i