cos20cos40cos60cos80=?
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/03 10:18:06
![cos20cos40cos60cos80=?](/uploads/image/z/11587414-22-4.jpg?t=cos20cos40cos60cos80%3D%3F)
cos20cos40cos60cos80=?
cos20cos40cos60cos80=?
cos20cos40cos60cos80=?
cos20cos40cos60cos80=sin40cos40cos60cos80/2sin20=cos60cos80sin80/4sin20=sin160cos60/8sin20=1/16
cos20cos40cos60cos80
=sin20cos20cos40cos80cos60/sin20
=sin40cos40cos80cos60
=1/2*sin80cos80cos60
=1/4*sin120cos60
结果就出来了