来自何余良的问题
已知tanx=-1/2,则sin?x+3sinxcosx-1=?
已知tanx=-1/2,则sin?x+3sinxcosx-1=?
1回答
2020-06-24 12:37
已知tanx=-1/2,则sin?x+3sinxcosx-1=?
已知tanx=-1/2,则sin?x+3sinxcosx-1=?
.sin��x+3sinxcosx-1
=(3sinxcosx-cos��x)/(sin��x+cos��x)
=(3tanx-1)/(tan��x+1)
=(3×(-1/2)-1)/[(-1/2)��+1]
=(-5/2)/(5/4)
=-2