计算cos40°/(cos25°√1-sin40°)等于

来源:学生作业帮助网 编辑:六六作业网 时间:2024/05/26 03:01:10
计算cos40°/(cos25°√1-sin40°)等于计算cos40°/(cos25°√1-sin40°)等于计算cos40°/(cos25°√1-sin40°)等于cos40°/(cos25°√1

计算cos40°/(cos25°√1-sin40°)等于
计算cos40°/(cos25°√1-sin40°)等于

计算cos40°/(cos25°√1-sin40°)等于
cos40°/(cos25°√1-sin40°)
=cos40°/[cos25°√(cos20°-sin20°)^2]
=cos40°/[cos25°(cos20°-sin20°)]
=(cos20°-sin20°)(cos20°+sin20°)/[cos25°(cos20°-sin20°)]
=(cos20°+sin20°)/cos25°
=√2 (cos20°sin45+sin20°cos45)/cos25°
=√2sin65°/cos25°
=√2