# First let's setup our sympy powered IPython Notebook environment...
from IPython.display import display, Latex
from sympy.interactive import printing
printing.init_printing()

import sympy
from sympy import *

x, k = sympy.symbols('x k')
f = sympy.Function('f')
dfdx_expr = x*sympy.exp(-k*x)
sol = dsolve(f(x).diff(x)-dfdx_expr,f(x))
sol

refine(sol, Q.is_true(Eq(k**3, 0)))

refine(sol, Q.is_true(Eq(k**3, 1)))