" If "sum_(n=0)^(oo)arccot((n^(2)+n+4)/(2))=K pi" then "Kis

If sum_(n=0)^(oo)2cot^(-1)((n^(2)+n+4)/(2))=k pi then find the value of k

If sum_(n=0)^(oo)2cot^(-1)((n^(2)+n+4)/(2))=k pi , then find the value of k.

If sum_(n=0)^oo2cot^(-1) ((n^2+n-4)/2)=kpi then find the value of k

sum_(n = 0)^(oo) ((2i)/(3))^n =

sum_(n=1)^(oo) (2n)/(n!)=

sum_(n=1)^(oo)(2 n^2+n+1)/((n!)) =

If 0 lt phi lt (pi)/(2) , x= sum_(n=0)^(oo) cos^(2n) phi ,y sum _(n=0)^(oo) sin ^(2n) phi and z = sum _(n=0) ^(oo) cos ^(2n) phi sin ^(2n) phi , then