Bài 1: Giải pt. a) \( 2\sin \left( x + \frac{\pi}{3} \right) + 1 = 0 \). b) \( 2\cos \left( x - \frac{\pi}{4} \right) - \sqrt{3} = 0 \). c) \( \sin x + \sin \left( 2x \cdot \frac{\pi}{4} \right) = 0 \). d) \( \cos \left( x + \frac{\pi}{6} \right) = -\sin x \)

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Bài 1: Giải pt.
a) \( 2\sin \left( x + \frac{\pi}{3} \right) + 1 = 0 \).
b) \( 2\cos \left( x - \frac{\pi}{4} \right) - \sqrt{3} = 0 \).
c) \( \sin x + \sin \left( 2x \cdot \frac{\pi}{4} \right) = 0 \).
d) \( \cos \left( x + \frac{\pi}{6} \right) = -\sin x \)