\( f^{\prime}(x)=\frac{1}{4} e^{\frac{1}{8} x-\frac{9}{5}}-\frac{1}{4} e^{-\frac{1}{8} x+\frac{9}{5}} \)
\( \frac{1}{4} e^{\frac{1}{8} x-\frac{9}{5}}-\frac{1}{4} e^{-\frac{1}{8} x+\frac{9}{5}}=0 \mid \cdot 4 \)
\( e^{\frac{1}{8} x-\frac{9}{5}}-e^{-\frac{1}{8} x+\frac{9}{5}}=0 \)
\( e^{\frac{1}{8} x-\frac{9}{5}}=e^{-\frac{1}{8} x+\frac{9}{5}} \)
Vergleich der Expononenten:
\( \frac{1}{8} x-\frac{9}{5}=-\frac{1}{8} x+\frac{9}{5} \mid+\frac{9}{5}+\frac{1}{8} x \)
\( \frac{2}{8} x=\frac{18}{5} \mid \cdot \frac{8}{2} \)
\( x=\frac{18}{5} \cdot \frac{8}{2}=14,4 \)