cos(x) = 1/2
tan(x) = y
1.04719755119660
1.73205080756888
5.23598775598299
-1.73205080756888
x1 = -5.235987755982989 y1 = 1.732050807568877
x2 = 1.047197551196598 y2 = 1.732050807568877