作业帮 > 数学 > 作业

已知非零常数 a,b满足(acosπ/5-bsinπ/5)/(asinπ/5+bcosπ/5)=1/(tan8π/15)

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/11/08 19:51:30
已知非零常数 a,b满足(acosπ/5-bsinπ/5)/(asinπ/5+bcosπ/5)=1/(tan8π/15),求b/a.
(acosπ/5-bsinπ/5)/(asinπ/5 bcosπ/5)=1/(tan8π/15),左边上下除以a.设b/a=k
cos8π/15sinπ/5+kcos8π/15cosπ/5=sin8π/15cosπ/5-ksinπ/5cos8π/15
kcos(8π/15-π/5)=sin(8π/15-π/5)
k=-tan(π/3)=-√3