cos1°+cos2°+cos3°+...+cos179°化简

分类: 作业答案 • 2022-01-04 12:23:36

问题描述：

答

cos1°=-cos179°
同理,cos2°=-cos178°,cos3°=-cos177°
则cos1°+cos179°=0
原式可简化为0+cos90°=0