Giải phương trình \(8.\cos 2x.\sin 2x.\cos 4x =  -...

Câu hỏi: Giải phương trình \(8.\cos 2x.\sin 2x.\cos 4x =  - \sqrt 2 .\)

A. \(\left[ \begin{array}{l}x = \frac{\pi }{{32}} + k\frac{\pi }{4}\\x = \frac{{3\pi }}{{32}} + k\frac{\pi }{4}\end{array} \right.{\rm{ }}\left( {k \in Z} \right).\)

B. \(\left[ \begin{array}{l}x = \frac{\pi }{8} + k\frac{\pi }{8}\\x = \frac{{3\pi }}{8} + k\frac{\pi }{8}\end{array} \right.{\rm{ }}\left( {k \in Z} \right).\)

C. \(\left[ \begin{array}{l}x =  - \frac{\pi }{{32}} + k\frac{\pi }{4}\\x = \frac{{5\pi }}{{32}} + k\frac{\pi }{4}\end{array} \right.{\rm{ }}\left( {k \in Z} \right).\)

D. \(\left[ \begin{array}{l}x = \frac{\pi }{{16}} + k\frac{\pi }{8}\\x = \frac{{3\pi }}{{16}} + k\frac{\pi }{8}\end{array} \right.{\rm{ }}\left( {k \in Z} \right).\)