[tex]\text{tg }\dfrac{5\pi}{6}+\cos\dfrac{\pi}{3}=\text{tg }\Big(-\dfrac{\pi}{6}\Big)+\cos\dfrac{\pi}{3}=-\text{tg }\dfrac{\pi}{6}+\cos\dfrac{\pi}{3}=\\\\\\=-\dfrac{\sqrt{3}}{3}+\dfrac{1}{2}=\dfrac{3-2\sqrt{3}}{6}\approx-0,077[/tex]
