2sin20°+（cos10°/cos20°）=

分类: 作业答案 • 2022-06-19 13:33:20

问题描述：

答

2sin20°+（cos10°/cos20°）
=(2sin20°cos20°+cos10°)/cos20°
=(sin40°+cos10°)/cos20°
=(sin40°+sin80°)/cos20°
=2sin60°cos20°/cos20°
=2sin60°
=√3