tan15°、tan75°sin15°、sin75°、cos15°cos75°具体数值
问题描述：
tan15°、tan75°sin15°、sin75°、cos15°cos75°具体数值
答
tan15
=tan*(45-30)
=2-√3
tan75sin15
=sin75/cos75×cos75
=sin15
=sin(45-30)
=(√6-√2)/4
sin75
=sin(45+30)
=(√6+√2)/4
cos15cos75
=sin15cos15
=1/2×sin30
=1/4
答
tan15°=2-根号3
tan75°=2+根号3
sin15°=(根号6-根号2)/4=cos75°
sin75°=(根号6+根号2)/4=cos15°