x*y = 1
x = 2*y
-1.4142135623731
-0.707106781186548
1.4142135623731
0.707106781186548
x1 = -1.414213562373095 y1 = -0.7071067811865475
x2 = 1.414213562373095 y2 = 0.7071067811865475