来自梁国平的问题
求值:sin415°-cos415°=______.
求值:sin415°-cos415°=______.
1回答
2020-05-10 17:37
求值:sin415°-cos415°=______.
求值:sin415°-cos415°=______.
sin415°-cos415°
=(sin215°+cos215°)(sin215°-cos215°)
=sin215°-cos215°
=-cos30°
=-
32