cosπ/8和sinπ/8怎么算啊

问题描述:

cosπ/8和sinπ/8怎么算啊
额 不好意思了都...

(cosπ/8)^2=(1+cosπ/4)/2=(2+根号2)/4
开方即得cosπ/8
同理(sinπ/8)^2=(1-cosπ/4)/2=(2-根号2)/4
开方即得sinπ/8