Please help, I am having problems answering the last part of this question below, the explaining if the graphs are the same or not. THANKS!

show that the solution of:

dy/dx = -((1+y^2)/(1+x^2)) y(0) = -1
is the inverse tan (x) + inverse tangent (y) = -pi/4 AND show that the above can be written :
y= ((x+1)/(x-1))
And are the graphs of:
inverse tan(x) + inverse tan (y) = -pi/4 AND y=((x+1)/(x-1)) from above the same?

Explain.

Question

Please help, I am having problems answering the last part of this question below, the explaining if the graphs are the same or not.  THANKS!

show that the solution of: 

dy/dx = -((1+y^2)/(1+x^2)) y(0) = -1 
is the inverse tan (x) + inverse tangent (y) = -pi/4 AND show that the above can be written : 
y= ((x+1)/(x-1)) 
And are the graphs of: 
inverse tan(x) + inverse tan (y) = -pi/4 AND y=((x+1)/(x-1)) from above the same? 

Explain.