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hackez


1. [TEX]Cos3x.Cos^3x - Sin3x.Sin^3x = \frac{2+3\sqrt[]{2}}{8}[/TEX]
2. [TEX]Cos^3x = \frac{Cos3x+3Cosx}{4}[/TEX]
3. [TEX]Sin2x + Sĩn - \frac{1}{2}Sinx - \frac{1}{Sin2x} = 2Cot2x[/TEX]
Cám ơn !
2. [TEX]Cos^3x = \frac{Cos3x+3Cosx}{4}[/TEX]
3. [TEX]Sin2x + Sĩn - \frac{1}{2}Sinx - \frac{1}{Sin2x} = 2Cot2x[/TEX]
Cám ơn !