Nghiệm của phương trình \(\cos \left( x+\frac{\pi }{4} \right)=\frac{\sqrt{2}}{2}\) là
A.\(\left[ \begin{array}{l}x = k2\pi \\x = - \frac{\pi }{2} + k\pi \end{array} \right.\,\left( {k \in } \right).\)
B.\(\left[ \begin{array}{l}x = k\pi \\x = - \frac{\pi }{2} + k\pi \end{array} \right.\,\left( {k \in } \right).\)
C.\(\left[ \begin{array}{l}x = k\pi \\x = - \frac{\pi }{2} + k2\pi \end{array} \right.\,\left( {k \in } \right).\)
D.\(\left[ \begin{array}{l}x = k2\pi \\x = - \frac{\pi }{2} + k2\pi \end{array} \right.\,\left( {k \in } \right).\)
A.\(\left[ \begin{array}{l}x = k2\pi \\x = - \frac{\pi }{2} + k\pi \end{array} \right.\,\left( {k \in } \right).\)
B.\(\left[ \begin{array}{l}x = k\pi \\x = - \frac{\pi }{2} + k\pi \end{array} \right.\,\left( {k \in } \right).\)
C.\(\left[ \begin{array}{l}x = k\pi \\x = - \frac{\pi }{2} + k2\pi \end{array} \right.\,\left( {k \in } \right).\)
D.\(\left[ \begin{array}{l}x = k2\pi \\x = - \frac{\pi }{2} + k2\pi \end{array} \right.\,\left( {k \in } \right).\)
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Hóa Học lớp 12
