求sin(-1320)cos1110+cos(-1020)sin750的值

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/29 01:34:43

求sin(-1320)cos1110+cos(-1020)sin750的值
求sin(-1320)cos1110+cos(-1020)sin750的值

求sin(-1320)cos1110+cos(-1020)sin750的值
1

sin(-1320)cos1110+cos(-1020)sin750
=sin(1440-1320)cos(960+150)+cos(-960-60)sin(720+30)
=sin120°cos150°+cos60°sin30°
=√3/2*(-√3)/2+1/4
=-3/4+1/4
=-1/2

sin(-1320)cos1110+cos(-1020)sin750=sin120cos30+cos60sin30=3/4+1/4=1