Question

tan^-1 x - tan^-1 y = π/4 where xy < 1 then find the value of x-y-xy

Answer 1

very hard and your answer

Answer 2

we know formula tan^-1x-tan^-1y/1+xy=pi/4
apply tan on both sides
(x-y/1+xy)=tanpi/4
x-y/1+xy=1
x-y=1+xy
x-y-xy=1
so 1 is answer