H
hoahue_91


có mấy bài lượng giác mọi người cùng làm nha
1, 1+sinx+cosx=2cos(x/2-pi/4)
2, tan^4x+tan^2x=4sin^2x
3, 4sin2x-3cos2x=3(4sinx-1)
4, 2cos^3x+cos2x+sinx=0
5, cos^5x+sin^7x+1/2(cos^3x+sin^5x)sin2x=sinx+cosx
6, 3(cotx-cosx)-5(tanx-sinx)=2
7, cosx.cos(x/2).cos(3x/2)-sinx.sin(x/2).sin(3x/2)=1/2
8, 9sinx+6cosx-3sin2x+cos2x=8
9, 5sin3x=3sin5x


moi nguoi lam giup cai
1, 1+sinx+cosx=2cos(x/2-pi/4)
2, tan^4x+tan^2x=4sin^2x
3, 4sin2x-3cos2x=3(4sinx-1)
4, 2cos^3x+cos2x+sinx=0
5, cos^5x+sin^7x+1/2(cos^3x+sin^5x)sin2x=sinx+cosx
6, 3(cotx-cosx)-5(tanx-sinx)=2
7, cosx.cos(x/2).cos(3x/2)-sinx.sin(x/2).sin(3x/2)=1/2
8, 9sinx+6cosx-3sin2x+cos2x=8
9, 5sin3x=3sin5x
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