因为角a的终边与单位圆的交点坐标为(1/2,-√3/2),
a=-60°+360°k
tana=tan(-60°+360°k)=tan(-60°)=-tan60°=-sqrt(3)
tan2a=tan2(-60°+360°k)
=tan(-120°+360°*2k)
==tan(-120°)=-tan120°
=tan60°=sqrt(3)
因为角a的终边与单位圆的交点坐标为(1/2,-√3/2),
a=-60°+360°k
tana=tan(-60°+360°k)=tan(-60°)=-tan60°=-sqrt(3)
tan2a=tan2(-60°+360°k)
=tan(-120°+360°*2k)
==tan(-120°)=-tan120°
=tan60°=sqrt(3)