`tan^(- 1) (1/(x+y)) +tan^(- 1) (y/(x^2+x y+1)) =cot^(- 1)x`

Prove that tan^(-1)(1/(x+y))+tan^(-1)(y/(x^2+xy+1) )= cot^(-1)x .

Prove the "tan"^(-1) 1/(x+y) + "tan"^(-1) y/(x^2=xy+1) ="tan"^(-1)1/x

Prove that tan ^(-1)""(1)/(x+y)+ tan ^(-1)""(y)/(x^(2)+xy+1)= cot ^(-1)x.

tan^(-1)(x/y)-tan^(-1)((x-y)/(x+y))=

tan^(-1)((x)/(y))-tan^(-1)((x-y)/(x+y)) is

tan^(-1)""(x)/(y)-tan^(-1)""(x-y)/(x+y)=

Tan^(-1)(x/y)-Tan^(-1)((x-y)/(x+y))=

If y = tan^(-1) ((1)/(1 + x + x^(2))) + tan^(-1) ((1) /(x^(2) + 2x + 3)) + tan^(-1) ((1)/(x^(2) + 5x + 7)) + ….n terms , then y(0) is