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

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

Prove that : tan^(-1)((x-y)/(1+xy)) + tan^(-1)((y-z)/(1+yz)) + tan^(-1)( (z-x)/(1+zx)) = tan^(-1)((x^2-y^2)/(1+x^2y^2))+tan^(-1)((y^2-z^2)/(1+y^2z^2))+tan^(-1)((z^2-x^2)/(1+z^2x^2))

Prove that: tan^(-1)((1-x)/(1+x))-tan^(-1)((1-y)/(1+y))=sin^(-1)((y-x)/(sqrt((1+x^(2))(1+y^(2)))))

If xy=1+a^(2) then show that tan^(-1)((1)/(a+x))+tan^(-1)((1)/(a+y))=tan^(-1)((1)/(a)),x+y+2a!=0

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

If tan^(-1) x + tan^(-1) y = (4pi)/(5) , then cot^(-1) x + cot^(-1) y equal to

If 2tan^(- 1)(c o s e c(tan^(- 1)(x))-tan(cot^(- 1)(x)))=tan^(- 1)y then y is equal to

Tan^(-1)((x)/(y))-Tan^(-1)((x-y)/(x+y)) is equal to