cosπ/7cos2π/7cos4π/7=?写下过程,谢谢~

来源：学生作业学帮网编辑：学帮网时间：2024/05/14 11:09:20

cosπ/7cos2π/7cos4π/7=?
写下过程,谢谢~

(sinπ/7cosπ/7cos2π/7cos4π/7)/sinπ/7=(0.5sin2π/7cos2π/7cos4π/7)/sinπ/7=(0.25sin4π/7cos4π/7)/sinπ/7=(0.125sin8π/7)/sinπ/7=(-0.125sinπ/7)/sinπ/7=-1/8