`""^(20)C_(0)-(""^(20)C_(1))/(2)+(""^(20)C_(2))/(3)-(""^(20)C_(3))/(4)+....`

Prove that (""^(n)C_(0))/(1)+(""^(n)C_(2))/(3)+(""^(n)C_(4))/(5)+(""^(n)C_(6))/(7)+...=(2^(n))/(n+1)

The value of ((""^(50)C_(0))/(1)+(""^(50)C_(2))/(3)+(""^(50)C_(4))/(5)+...+(""^(50)C_(50))/(51)) a) (2^(50))/(51) b) (2^(50)-1)/(51) c) (2^(50)-1)/(50) d) (2^(51)-1)/(51)

""^(11)C_(0)+""^(11)C_(1)+""^(11)C_(2)+""^(11)C_(3)+""^(11)C_(4)+""^(11)C_(5)=