其他 返回
天气预报 > 其他 > 两角差的余弦公式推导五种方法
两角差的余弦公式推导五种方法
更新时间： 2020-10-30 00:00:00  

两角差的余弦公式：cos（α－β）＝cosαcosβ＋sinαsinβ。可以用：向量法，两点间距离法，复数法，高斯公式法，几何法推导。

举例：复数推导法

(cosa+isina)(cos(-b)+isin(-b))=cos(a-b)+isin(a-b)

(cosa+isina)(cos(-b)+isin(-b))=(cosacosb+sinasinb)+i(sinacosb-cosasinb)

比较实部和虚部得：

cos(a-b)=cosacosb+sinasinb

sin(a-b)=sinacosb-cosasinb

关键词： 余弦 公式 推导 方法

两角差的余弦公式推导五种方法相关经验

天气预报

最新推荐

页面:/news/view-1367692/ | 耗时:0.0725 s | 内存:2.11 MB | 查询:4 | 缓存读取:3 写入:0 | 加载文件:25
select * from tbl_Articles WHERE ArticleID=1367692 LIMIT 0,1
select * from tbl_Articles_data WHERE ArticleID=1367692 LIMIT 0,1
select * from tbl_Articles_sphinx where id=1367692 LIMIT 0,1
SELECT ArticleID,Title FROM tbl_Articles WHERE ArticleID IN(1101847,1110658,1077074,1073722,1106711,1066090,1087793,1043609,1085888,1091950,1116315,1121578,1097575,1098389,1104657,1077100,1092920,1112889,1102437,1111130,1117189,1108448,1078332,964762,1077533,1078735,1087926,1108990,1093657,1085162) ORDER BY field (ArticleID,1101847,1110658,1077074,1073722,1106711,1066090,1087793,1043609,1085888,1091950,1116315,1121578,1097575,1098389,1104657,1077100,1092920,1112889,1102437,1111130,1117189,1108448,1078332,964762,1077533,1078735,1087926,1108990,1093657,1085162)