问题
填空题
求值:sin415°-cos415°=______.
答案
sin415°-cos415°
=(sin215°+cos215°)(sin215°-cos215°)
=sin215°-cos215°
=-cos30°
=-
.3 2
故答案为:-
.3 2
求值:sin415°-cos415°=______.
sin415°-cos415°
=(sin215°+cos215°)(sin215°-cos215°)
=sin215°-cos215°
=-cos30°
=-
.3 2
故答案为:-
.3 2