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PT$\Leftrightarrow 2\sin\frac{6x}{2}\cos\frac{4x}{2}+2(\frac{1-\cos2z}{2})-1=0\\\Leftrightarrow 2\sin3x\cos2x-\cos2x=0\\\Leftrightarrow \cos2x(2\sin3x-1)=0\\\Leftrightarrow \left[ \begin{matrix} \cos2x = 0 (1)\\ \sin3x = \frac{1}{2} (2) \end{matrix}{} \right.$
Giải pt (1), (2) ra nghiệm.
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