

giải phương trình
1, (sinx.cot5x)/cot9x=1
2, (cosx-2sinxcosx)/(2cos^2x-sinx-1)=căn3
3, sin5x/(5sinx)=1
4, 1+cot2x=(1-cos2x)/sin^2x
5, sin3x= cosx.cos2x.(tan^2x+tan2x)
1, (sinx.cot5x)/cot9x=1
2, (cosx-2sinxcosx)/(2cos^2x-sinx-1)=căn3
3, sin5x/(5sinx)=1
4, 1+cot2x=(1-cos2x)/sin^2x
5, sin3x= cosx.cos2x.(tan^2x+tan2x)