计算:cos(π/8)*sin(π/8)=?麻烦各位了,知道的就快告诉我,在写谢谢了,要过程或详解哦
问题描述:
计算:cos(π/8)*sin(π/8)=?
麻烦各位了,知道的就快告诉我,在写谢谢了,要过程或详解哦
答
sinπ/4=sin(π/8+π/8)
开方2/2= 2sinπ/8cosπ/8
sinπ/8cosπ/8 = (开方2)/4
答
根据2*cos(x)*sin(x)=sin(2x)
得cos(π/8)*sin(π/8)=0.5*sin(π/4)=四分之根号2
答
cos(π/8)*sin(π/8)=1/2*(2*cos(π/8)*sin(π/8))=1/2*sin(π/4)
=根号2/4