Question

I have part one and part 2, but I am having trouble with the third part asking if the graphs are the same and to explain my answer:

Show that the solution of dy/dx = - (1+y^2)/(1+x^2) when y(0) = -1
is tan inverse (x) + tan inverse (y) = - pi/4

AND

Show that tan inverse (x) + tan Inverse (y) = -pi/4 can be written as :
y = (x+1)/(x-1)

So my problem is this third part -

are the graphs of tan inverse (x) +tan inverse (y) = -pi/4 AND y=(x+1)/(x-1) the same?? EXPLAIN YOUR ANSWER....PLEASE HELP! Thanks!