Find the sum of the series
`cot^(-1) 7+cot^(-1)13+cot^(-1)21+cot^(-1)31+...` to n terms

The sum of the series cot^(-1)2+cot^(-1)8+cot^(-1)18+cot^(-1)32.........

Find- cot^(-1)1+cot^(-1)2+cot^(-1)3

Prove that cot^(-1)7+cot^(-1)8+cot^(-1)18=cot^(-1)3

Find the sum to n terms cot^(-1)(3)+cot^(-1)(7)+cot^(-1)(13)+cot^(-1)21

Prove that : cot^(-1)7+cot^(-1)8+cot^(-1)18=cot^(-1)3

Prove that : cot^(-1)7+cot^(-1)8+cot^(-1)18=cot^(-1)3

Prove that : cot^(-1)7+cot^(-1)8+cot^(-1)18=cot^(-1)3

If the sum of the series cot^(-1)2+cot^(-1)8+cot^(-1)18+…+cot^(-1)2n^(2)+…… " upto "infty " is "(kpi)/4 then the value of K is