`sum_(k=1)^n k/(k^4+1/4)=`

sum_(k=1)^n k^3=

sum_(k =1)^(n) k(1 + 1/n)^(k -1) =

Prove that sum_(k=1)^n 1/(k(k+1))=1−1/(n+1) .

Find the value of 2551 S where S = sum_(k=1)^(50) k/(k^(4)+k^(2)+1)

If a_(k)=(1)/(k(k+1)) for k=1,2,3, .. , n, then (sum_(k=1)^(n) a_(k))^(2)=

The limit of (1)/(n ^(4)) sum _(k =1) ^(n) k (k +2) (k +4) as n to oo is equal to (1)/(lamda), then lamda =

The limit of (1)/(n ^(4)) sum _(k =1) ^(n) k (k +2) (k +4) as n to oo is equal to (1)/(lamda), then lamda =

If z_(k)=e^(i theta_k) for k= 1, 2, 3, 4 where i^(2)= -1 , and if |sum_(k=1)^(4) (1)/(z_k)|=1 , then |sum_(k=1)^(4)| is equal to

The sum sum_(k=1)^(100)(k)/(k^(4)+k^(2)+1) is equal to

If a_(k) = (1)/( k(k+1) ) for k= 1,2,3,….n then (sum_(k=1)^(n) a_(k) )=