sin十分之派乘cos五分之派怎么算

来源:学生作业帮助网 编辑:六六作业网 时间:2024/05/09 22:04:10
sin十分之派乘cos五分之派怎么算sin十分之派乘cos五分之派怎么算sin十分之派乘cos五分之派怎么算sinπ/10*cosπ/5=(cosπ/10*sinπ/10*cosπ/5)/(cosπ/

sin十分之派乘cos五分之派怎么算
sin十分之派乘cos五分之派怎么算

sin十分之派乘cos五分之派怎么算
sinπ/10*cosπ/5
=(cosπ/10*sinπ/10*cosπ/5)/(cosπ/10)
=(1/2sinπ/5cosπ/5)/(cosπ/10)
=(1/4sin2π/5)/sin(π/2-π/10)
=(1/4sin2π/5)/sin2π/5
=1/4