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pvanpvan


tim x thuộc (0,pi) thoa man phương trình
[TEX]cotx-1=\frac{cos2x}{1+tanx}+ sin^2 x-\frac{1}{2}sin2x[/TEX]
[TEX]cotx-1=\frac{cos2x}{1+tanx}+ sin^2 x-\frac{1}{2}sin2x[/TEX]
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