Find the sum `sum_(k=0)^(10)^(20)C_kdot`

Find the sum sum_(r=0)^n^(n+r)C_r .

Find the sum sum_(j=0)^(n) (""^(4n+1)C_(j)+""^(4n+1)C_(2n-j)) .

Find the sum sum_(j=1)^(10)sum_(i=1)^(10)ixx2^(j)

Find the sum sum_(i=0)^r.^(n_1)C_(r-i) .^(n_2)C_i .

Find the sum_(k=1)^(oo) sum_(n=1)^(oo)k/(2^(n+k)) .

The value of sum_(r=0)^(10)(r)^(20)C_r is equal to: a. 20(2^(18)+^(19)C_(10)) b. 10(2^(18)+^(19)C_(10)) c. 20(2^(18)+^(19)C_(11)) d. 10(2^(18)+^(19)C_(11))

Find the sum ^10 C_1+^(10)C_3+^(10)C_5+^(10)C_7+^(10)C_9dot

Find the sum sum_(r=1)^n r^2(^n C_r)/(^n C_(r-1)) .

Find the sum of sum_(r=1)^n(r^n C_r)/(n C_(r-1) .

Find the sum sumsum_(0leiltjlen)"^nC_i