CÁC BẠN GIÚP MÌNH VỚI Ạ ^_^1)\(\sin^2x+\sin^22x+\sin^23x=\frac{3}{2}\)2) \(\cos^2x+\cos^22x+\cos^23x=1\)3) \(\cos^2x+\cos^22x+\cos^23x+\cos^24x=2\)4) \(\sin2x=1+\sqrt{2}\cos x+\cos2x\)5) \(\sin x\left(1+\cos x\right)=1+\cos x+\cos^2x\)6) \(\left(2\sin x-1\right)\left(2\cos2x+\sin2x+1\right)=3-4\cos^2x\)7) \(\sin x+\sin2x+\sin3x=\sqrt{2}\left(\cos x+\cos2x+\cos3x\right)\)8) \(\cos5x\cos x=\cos4x\cos2x+3\cos^2x+1\)9) \(\sin7x+\cos^22x=\sin^22x+\sin x\)10) ...
Đọc tiếp
CÁC BẠN GIÚP MÌNH VỚI Ạ ^_^
1)\(\sin^2x+\sin^22x+\sin^23x=\frac{3}{2}\)
2) \(\cos^2x+\cos^22x+\cos^23x=1\)
3) \(\cos^2x+\cos^22x+\cos^23x+\cos^24x=2\)
4) \(\sin2x=1+\sqrt{2}\cos x+\cos2x\)
5) \(\sin x\left(1+\cos x\right)=1+\cos x+\cos^2x\)
6) \(\left(2\sin x-1\right)\left(2\cos2x+\sin2x+1\right)=3-4\cos^2x\)
7) \(\sin x+\sin2x+\sin3x=\sqrt{2}\left(\cos x+\cos2x+\cos3x\right)\)
8) \(\cos5x\cos x=\cos4x\cos2x+3\cos^2x+1\)
9) \(\sin7x+\cos^22x=\sin^22x+\sin x\)
10) \(\sin2x+\left(1+2\cos3x\right)\sin x-2\sin^2\left(2x+\frac{\pi}{4}\right)=0\)
11) \(\sqrt{3}\cos5x-2\sin3x\cos2x-\sin x=0\)
12) \(4\cos\frac{5x}{2}\cos\frac{3x}{2}+2\left(8\sin x-1\right)\cos x=5\)
