minimize (sin(x) / cos[ arcsin(2 / 3) - x ] + cos(x) / sin[ arcsin(2 / 3) - x ] + sin[ arcsin(2 / 3) - x ] / cos(x) + cos[ arcsin(2 / 3) - x ] / sin(x)) for 0<x<pi/2, 0<y<pi/2