来自刘密英的问题
【sin(-1071度)×sin99度+sin(-171度)sin(-261度)化简】
sin(-1071度)×sin99度+sin(-171度)sin(-261度)化简
1回答
2020-04-11 21:41
【sin(-1071度)×sin99度+sin(-171度)sin(-261度)化简】
sin(-1071度)×sin99度+sin(-171度)sin(-261度)化简
sin(-1071°)×sin99°+sin(-171°)sin(-261°)
=sin(1080°-1071°)×sin(90°+9°)°+sin(360°-171°)sin(-261°+360°)
=sin9°*cos9°+sin(-9°)*cos9°
=sin9°*cos9°-sin9°*cos9°
=0