[Python] Symbolic derivative with sympy of a symbolic function

If I define a variable e.g. $ V = f(r) * x^2 $ and I choose $f(r)$ as a symbolic function with $ r = \sqrt(x^2+y^2+z^2) $. Now I take the derivative of V with respect to x and want to get the solution from sympy, then the result is:

x**3*Subs(Derivative(f_A(_xi_1), _xi_1), _xi_1, sqrt(x**2 + y**2 + z**2))/sqrt(x**2 + y**2 + z**2) + 2*x*f_A(sqrt(x**2 + y**2 + z**2))


Its possible to get a symbolic output for the derivative like $ \frac{x^3}{r} df(r)/dx + 2x f(r) $

import sympy as sp

x, y, z = sp.symbols('x y z')
r = sp.sqrt(x**2 + y**2 + z**2)
f_A = sp.Function('f_A')(r)

V = f_A * x**2

dV_dx = sp.diff(V, x)

print(dV_dx)

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