Kettenregel:
\phi(t) = F(g(t)); \quad \dot\phi(t) = F'(g(x)) \cdot g'(t);φ(t) = F(g(t));φ̇(t) = F′(g(x)) ⋅ g′(t);
\int f(g(t)) g'(t) \,\mathrm{d}t = F(g(t)) + C = \int f(x) \,\mathrm{d}x∫ f(g(t))g′(t)dt = F(g(t)) + C = ∫ f(x)dx mit x = g(t);x = g(t);