tan(x) = 0
pi x + y = -- 4
x + y = pi/4
0
0.785398163397448
x1 = -6.283185307179586 y1 = 7.068583470577035
x2 = 9.42477796076938 y2 = -8.639379797371932
x3 = 3.141592653589793 y3 = -2.356194490192345
x4 = 6.283185307179586 y4 = -5.497787143782138
x5 = -9.42477796076938 y5 = 10.21017612416683
x6 = -3.141592653589793 y6 = 3.926990816987242
x6 = -3.141592653589793 y6 = 3.926990816987242