Решите уравнение \(\cos t =-\frac{1}{2}.\)

• \(\pm \frac{2\pi}{3}+2\pi n, n\in Z\)
• \(\frac{2\pi}{3}+2\pi n, n\in Z\)
• \(-\frac{\pi}{3}+2\pi n, -\frac{2\pi}{3}+2\pi n, n\in Z\)
• \(\pm \frac{5\pi}{6}+2\pi n, n\in Z\)