Find the equation of the hyperbola according to the following condition.
Two points F(1,-1) and F'(-1,1) are foci.
The difference of distances from two foci is 2.
Applet
Press "n+" to draw circles whose center points are F or F'.
The difference of the distances from each blue point to F and F' is 2.
Find the equation of hyperbola when it is rotated by 45 degrees around the origin.