Решите уравнение: \(\huge cos4x=1.\)

• \(\huge {x= {{ \pi k} \over {2}}, k \in Z}\)
• \(\huge {x= {{ \pi} \over {8}} +{{ \pi k} \over {4}}, k \in Z}\)
• \(\huge {x= {{ \pi} \over {4}} +{{ \pi k} \over {4}}, k \in Z}\)
• \(\huge {x= 4 \pi +{{ \pi k} \over {2}}, k \in Z}\)