Differentialregning
Fin introduktion med Newton, Leibniz og Usain Bolt:
https://www.khanacademy.org/math/calculus/differential-calculus/intro_differential_calc/v/newton-leibniz-and-usain-bolt
https://www.khanacademy.org/math/calculus/differential-calculus/intro_differential_calc/v/newton-leibniz-and-usain-bolt