stats.std for error propegation does not return

[loworbitmoonsun]

The following code to implement error propegation does not work. Sympy hangs on the calculation of the standard deviation without returning error. Seems to be looping internally as can be seen with pdb.

Is this a known issue? Any help would be appreciated.

import sympy.stats
import scipy

v0 = 200
x0 = 100
y0 = 50
g = 9.81

V = sp.stats.Normal('v', v0, 1)
T = sp.stats.Normal('t', sp.pi/4, sp.pi/180)
xmax = V**2*sp.sin(T)*sp.cos(T)/g + x0
Sx = sp.stats.std(xmax)
print(Sx)

[oscarbenjamin]

Looks like it gets stuck in the heurisch integration routine.