import sympy as sp

K0 = 2.00*10**-4
x2, y2 = sp.symbols('x2, y2')
x0 = 500
y0 = 500
R1 = ((x2 - x0)**2 + (y2 - y0)**2)**0.5
R2 = K0 * R1
H2 = sp.atan(R2 * (x2 - x0)/R1)
V2 = sp.atan(R2 * (y2 - y0)/R1)
x, y = sp.symbols('x, y')
x0 = 1.0
y0 = 2.0
x = R1 * H2
y = R1 * V2
dat = sp.nsolve([x - x0, y - y0], [x2, y2], [512, 512]) # This line is the problem
print "dat = %f, %f" % (dat[0], dat[1])

File "test.py", line 3, in <module>
    demo.test()
  File "demo.pyx", line 17, in demo.test
    dat = sp.nsolve([x - x0, y - y0], [x2, y2], [512, 512])
  File "C:...site-packagessympyutilitiesdecorator.py", line 91, in func_wrapper
    return func(*args, **kwargs)
  File "C:...site-packagessympysolverssolvers.py", line 2847, in nsolve
    x = findroot(f, x0, J=J, **kwargs)
  File "C:...site-packagesmpmathcalculusoptimization.py", line 960, in findroot
    for x, error in iterations:
  File "C:...site-packagesmpmathcalculusoptimization.py", line 658, in __iter__
    s = self.ctx.lu_solve(Jx, fxn)
  File "C:...site-packagesmpmathmatriceslinalg.py", line 227, in lu_solve
    A, p = ctx.LU_decomp(A)
  File "C:...site-packagesmpmathmatriceslinalg.py", line 137, in LU_decomp
    raise ZeroDivisionError('matrix is numerically singular')
ZeroDivisionError: matrix is numerically singular