问题
填空题
cos43°sin13°+sin43°cos167°的值为______.
答案
cos43°sin13°+sin43°cos167°=sin13°cos43°-sin43°cos13°
=sin(13°-43°)=sin(-30°)=-sin30°=-
,1 2
故答案为:-
.1 2
cos43°sin13°+sin43°cos167°的值为______.
cos43°sin13°+sin43°cos167°=sin13°cos43°-sin43°cos13°
=sin(13°-43°)=sin(-30°)=-sin30°=-
,1 2
故答案为:-
.1 2