Find the value of `sum_(r=0)^ootan^(-1)(1/(1+r+r^2))`

Find the value of sum_(r=0)^(oo)tan^(-1)(1/(1+r+r^2))

Find the value of sum_(r=0)^(oo) tan^(-1) ((1)/(1 + r + r^(2)))

Find the value of sum_(r=0)^(oo) tan^(-1) ((1)/(1 + r + r^(2)))

Find the value of sum_(r=1)^(4)(2+tan((2r-1)(pi)/(8))*tan((2r+1)(pi)/(8)))

Find the value of sum_(r=1)^(n) (r)/(1+r^(2)+r^(4))

Find the value of sum_(r=1)^(4)(2+tan(((2r-1)pi)/(8))*tan(((2r+1)pi)/(8)))

The value of sum_(r=1)^(oo)tan^(-1)((2r-1)/(r^(4)-2r^(3)+r^(2)+1)) is equal to

If sum_(r = 1)^(oo) (1)/((2r - 1)^2) = (pi^2)/(8) then the value of sum_(r = 1)^(oo) (1)/(r^2) is

The value of sum_(r=1)^(10)r.r! is

If z_(r):r=1,2,3,,50 are the roots of the equation sum_(r=0)^(50)z^(r)=0, then find the value of sum_(r=0)^(50)(1)/(z_(r)-1)