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tamcat
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1, 3-4 sin^2 2x= 2 cos2x* (1+ 2sinx)
2, 2 cosx+1/3 *cos^2 (x+ pi)=8/3 +sin 2x+3cos(x+pi/2)+ 1/3 * sin^2 x
3, cos^2(x+pi/3)+cos^2 (x+2pi/3)=(sinx+1)/2
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2, 2 cosx+1/3 *cos^2 (x+ pi)=8/3 +sin 2x+3cos(x+pi/2)+ 1/3 * sin^2 x
3, cos^2(x+pi/3)+cos^2 (x+2pi/3)=(sinx+1)/2
Cac ban cố lam nha,cảm ơn nhiều