Uprav daný výraz:
\( \cos \frac{23 \pi}{6}+\sin \frac{4 \pi}{3}+\operatorname{cotg} \frac{\pi}{6} \cdot \operatorname{tg} \frac{5 \pi}{6}+\cos \frac{5 \pi}{2} \)
\( 2 \)
\( 1 \)
\( -1 \)
\( 0 \)
