A.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] = - \dfrac{{\sqrt 3 }}{2}\)
B.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] = - \dfrac{{\sqrt 2 }}{2}\)
C.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] = - \dfrac{1}{2}\)
D.\(\cos \left[ {\dfrac{\pi }{4} + \left( {2k + 1} \right)\pi } \right] = \dfrac{{\sqrt 3 }}{2}\)
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Hóa Học lớp 12
