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\( \frac{d y}{y}=\frac{4 x^{3}}{1+x^ 4} d x \)
\( \begin{aligned} ln|y| &=\ln \left|1+x^{4}\right|+c---> \ e^{hoch} \\ |y | &=e^{\ln \left|1 + x^{4}\right|+c}=\left(1+x^{4}\right) e^{c} \\ y &=\left(1 + x^{4}\right) \cdot \pm e^{c} \\ y &=c_{1} \cdot\left(1+x^{4}\right) \end{aligned} \)