LaTeX output of sympy formulas

latex.py

from sympy import *
from sympy.printing.mathml import mathml
init_printing(use_unicode=True) # allow LaTeX printing

# independent variables
x, y, z = symbols('x y z', real = True)

# parameters
nu, rho = symbols('nu rho', real = True, constant = True, positive = True)

# dependent variables
u, v, w = symbols('u v w', real = True, cls = Function)

print(latex(diff(u(x,y,z),x)))