Is sin(A) = cos(B) then one of two relations hold.
1: A and B are complementary, which implies A+B = pi/2 +/- 2*pi*n (n is an integer)
2: A is a phase shift of B, which implies A-B = pi/2 +/- 2*pi*n
In the first case, the equation can be simplified to a set of concentric circles (x+1/2)^2 + (y+1/2)^2 = 1/4+pi/2 + 2*pi*n
In the second case, the equation can be simplified to another set of concentric circles (x-1/2)^2 + (y-1/2)^2 = 1/4+3*pi/2 + 2*pi*n
In both cases the smallest members are found when n=0.
(x+1/2)^2 + (y+1/2)^2 = 1/4+pi/2
(x-1/2)^2 + (y-1/2)^2 = 1/4+3*pi/2