ConceptPythonBeginner Computer algebra: formulas as trees, exact until you ask for digits dexpr = sp.diff(expr, t)
ToolPythonBeginner SymPy from the ground up: where the pendulum's 1.74 % comes from dE_dt = sp.diff(E_t, t)dtheta_dphi = sp.diff(theta_of_phi, phi)