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minhcantho
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
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1.[TEX]tan^2(x)+cot^2(x)+cot^2(2x)=\frac{11}{3}[/TEX]
2.[TEX]sin^2(\frac{x}{2}-\frac{\pi}{4}).tan^2(x)-cos^2(\frac{x}{2})=0[/TEX]
3.[TEX]sin^4(x)+cos^4(x)=\frac{7}{8}.cot(x+\frac{\pi}{3})cot(\frac{\pi}{6}-x) [/TEX]
4. [TEX]sin^4(x)+cos^4(x)=\frac{-5}{8}.tan(x+\frac{\pi}{4})tan(x-\frac{\pi}{4})[/TEX]
2.[TEX]sin^2(\frac{x}{2}-\frac{\pi}{4}).tan^2(x)-cos^2(\frac{x}{2})=0[/TEX]
3.[TEX]sin^4(x)+cos^4(x)=\frac{7}{8}.cot(x+\frac{\pi}{3})cot(\frac{\pi}{6}-x) [/TEX]
4. [TEX]sin^4(x)+cos^4(x)=\frac{-5}{8}.tan(x+\frac{\pi}{4})tan(x-\frac{\pi}{4})[/TEX]
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