cosacosb=1,则cos(a-b)的值为多少呢

来源：学生作业帮编辑：神马作文网作业帮分类：数学作业时间：2024/11/23 23:27:54

cosacosb=1,只能是cosa=cosb=1或cosa=cosb=-1
此时必有sina=0,sinb=0
于是：cos(a-b)=cosacosb+sinasinb=1+0=1

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