\section*{Aufgabe 4} \begin{align*} I = \int_0^1 \frac{1}{1+4x} dx = \int_0^{0.5} \frac{1}{1+4x} dx +\int_{0.5}^{1} \frac{1}{1+4x} dx = \\ (0.5 - 0) * \frac{f(0) + f(0.5)}{2} + (1 - 0.5) * \frac{f(1) + f(0.5)}{2} = \frac{7}{15} \end{align*}