`tan^(-1)((x+y)/(1-xy)),xy<1`=

If x,y are real numbers such that xy<1 then tan^(-1)x+tan^(-1)y=tan^(-1)((x+y)/(1-xy))

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

The result tan^(-1)x-tan^(-1)y = tan^(-1)((x-y)/(1+xy)) is true when the value of xy is "………."

tan^(-1)x-tan^(-1)y=tan^(-1)((x-y)/(1+xy)) holds good for

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

Q.tan^(^^)-1x+tan^(^^)-1y=pi+tan^(^^)-1((x+y)/(1-xy)) if x,y>0 and xy>0Q*cos^(^^)-1x+cos^(^^)-1y=2pi-cos^(^^)-1(xy-sqrt(1-x^(^^)2)sqrt(1-y^(^^)2)) if x+y<0

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

" (a) "tan^(-1)x+tan^(-1)y+tan^(-1)z=tan^(-1)(x+y+z-xyz)/(1-xy-yz-zx)

The solution of (dy)/(dx)=((x-1)^(2)+(y-2)^(2)tan^(-1)((y-2)/(x-1)))/((xy-2x-y+2)tan^(-1)((y-2)/(x-1))) is equal to