Задание
Решите уравнение: \(\large\cos{x}=\cos{3x}\)
- \(\large\mathtt{x=\frac{\pi{n}}{2}, n\in{Z}}\)
- \(\large\mathtt{x=\pi{n}, n\in{Z}}\)
- \(\large\mathtt{x=\frac{\pi}{2}+\pi{n}, n\in{Z}}\)