Giải phương trình \({\sin ^4}x + {\cos ^4}x = \dfrac{7}{8}\cot \left( {x + \dfrac{\pi }{3}} \right).\cot \left( {\dfrac{\pi }{6} - x} \right)\).
A.\(\left[ \begin{array}{l}x = \dfrac{\pi }{{12}} + \dfrac{{k\pi }}{2}\\x = - \dfrac{\pi }{{12}} + \dfrac{{k\pi }}{2}\end{array} \right.\)
B.\(\left[ \begin{array}{l}x = \dfrac{\pi }{6} + \dfrac{{k\pi }}{2}\\x = - \dfrac{\pi }{6} + \dfrac{{k\pi }}{2}\end{array} \right.\)
C.\(\left[ \begin{array}{l}x = \dfrac{\pi }{3} + \dfrac{{k\pi }}{2}\\x = - \dfrac{\pi }{3} + \dfrac{{k\pi }}{2}\end{array} \right.\)
D.Đáp án khác.
A.\(\left[ \begin{array}{l}x = \dfrac{\pi }{{12}} + \dfrac{{k\pi }}{2}\\x = - \dfrac{\pi }{{12}} + \dfrac{{k\pi }}{2}\end{array} \right.\)
B.\(\left[ \begin{array}{l}x = \dfrac{\pi }{6} + \dfrac{{k\pi }}{2}\\x = - \dfrac{\pi }{6} + \dfrac{{k\pi }}{2}\end{array} \right.\)
C.\(\left[ \begin{array}{l}x = \dfrac{\pi }{3} + \dfrac{{k\pi }}{2}\\x = - \dfrac{\pi }{3} + \dfrac{{k\pi }}{2}\end{array} \right.\)
D.Đáp án khác.
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Hóa Học lớp 12
