化简 sin119°sin181°-sin91°sin29°= 写个过程啊~
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/22 07:45:03
![化简 sin119°sin181°-sin91°sin29°= 写个过程啊~](/uploads/image/z/956008-64-8.jpg?t=%E5%8C%96%E7%AE%80+sin119%C2%B0sin181%C2%B0-sin91%C2%B0sin29%C2%B0%3D+%E5%86%99%E4%B8%AA%E8%BF%87%E7%A8%8B%E5%95%8A%7E)
化简 sin119°sin181°-sin91°sin29°= 写个过程啊~
化简 sin119°sin181°-sin91°sin29°= 写个过程啊~
化简 sin119°sin181°-sin91°sin29°= 写个过程啊~
原式=sin(180-61)sin(180+1)-sin(180-89)sin29
=-sin61sin1-sin89sin29
=-[sin(90-29)sin1+cos(90-89)sin29]
=-(cos29sin1+cos1sin29)
=-sin(1+29)
=-sin30
=-1/2