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snowangel1103


a) [TEX]1+cos2x+cos3x = 2cosx.cos2x[/TEX]
b[TEX]\frac{cos^2x}{sinx+cos(7pi+x)}=2(1+sinx)[/TEX]
b[TEX]\frac{cos^2x}{sinx+cos(7pi+x)}=2(1+sinx)[/TEX]
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