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[TEX]cos(9x)+2cos(3x)+\sqrt{2}sin(3x+\frac{pi}{4}=3sin(x)[/TEX]
[TEX]sin^4(3x+\frac{pi}{4})+sin^4(3x-\frac{pi}{4})=\frac{1}{2}[/TEX]
[TEX]sin^4(3x+\frac{pi}{4})+sin^4(3x-\frac{pi}{4})=\frac{1}{2}[/TEX]