Решите уравнение: \(\huge {cos2x= {{ \sqrt {2}} \over {2}}}.\)

• \(\huge {x= \pm {{ \pi} \over {8}} + \pi k, k \in Z}\)
• \(\huge {x= \pm {{ \pi} \over {2}} + \pi k, k \in Z}\)
• \(\huge {x= \pm {{ \pi} \over {12}} + \pi k, k \in Z}\)
• \(\huge {x= \pm {{ 5\pi} \over {12}} + \pi k, k \in Z}\)