

1) [tex]cos^{4}(x-\frac{5\Pi }{2}) + sin^{4}x =2[/tex]
2) [tex]\frac{cosx -2sinx.cosx}{2cos^{2}x+sinx-1}=\sqrt{3}[/tex]
3) [tex]tanx = cotx +2cot^{3}2x[/tex]
4) [tex]cos^{4}x -cos2x +2sin^{6}x =0[/tex]
mn giúp mình với ạ
2) [tex]\frac{cosx -2sinx.cosx}{2cos^{2}x+sinx-1}=\sqrt{3}[/tex]
3) [tex]tanx = cotx +2cot^{3}2x[/tex]
4) [tex]cos^{4}x -cos2x +2sin^{6}x =0[/tex]
mn giúp mình với ạ