Urči periodu funkce:
\( f(x)=\sin \left(\frac{6 x}{7}+\pi\right) \)
\( \frac{6 \pi}{7} \)
\( \frac{7 \pi}{3} \)
\( \frac{14 \pi}{3} \)
\( \frac{7 \pi}{6} \)
