The value of `sum_(x=1)^n (-1)^(r+1) (C(n,r))/(r+1)` is equal to

The value of sum_(r=1)^(n)(-1)^(r+1)(^nCr)/(r+1) is equal to a.-(1)/(n+1) b.(1)/(n) c.(1)/(n+1) d.(n)/(n+1)

sum_(r=1)^(n)(C(n,r))/(r+2) is equal to

The value of sum_(r=0)^(2n)(-1)^(r)*(""^(2n)C_(r))^(2) is equal to :

If sum_(r=1)^(n)T_(r)=(n(n+1)(n+2))/(6), then the value of sum_(r=1)^(oo)((1)/(T_(r))) is equal to

If f(n)=sum_(r=1)^(n) r^(4) , then the value of sum_(r=1)^(n) r(n-r)^(3) is equal to

The value of Sigma_(r=1)^(n)(-1)^(r+1)(""^(n)C_(r))/(r+1)) is equal to

The value sum_(r=1)^(10)r.(n_(C_(r)))/(n_(C_(r-1))) is equal to

The value of sum_(r=0)^(n-1)(nC_(r))/(nC_(r)+^(n)C_(r+1)) is eqaul to