sin100°(1+根号三tan10°)=
问题描述：
sin100°(1+根号三tan10°)=
答
sin50（1+√3tan10）
=sin50[1+√3(sin10/cos10)]
=sin50[(cos10+√3sin10)/cos10]
=sin50[2sin(30+10)/cos10]
=(2sin50sin40)/cos10°
=(2cos40°*sin40°)/cos10°
=sin80°/cos10°
=cos10°/cos10°
=1
答
答：
sin100°(1+√3tan10°）
=sin100°[1+√3(sin10°/cos10°)]
=sin100°[(cos10°+√3sin10°)/cos10°]
=sin100°[2sin(30°+10°)/cos10°]
=(2sin80°sin40°)/cos10°
=(2cos10°sin40°)/cos10°
=2sin40°