已知tan a=3,求tan（a+π/4）,tan(a-π/4)的值?没有分了,不好意思 .
问题描述：
已知tan a=3,求tan（a+π/4）,tan(a-π/4)的值?
没有分了,不好意思 .
答
已知tan a=3，求tan（a+π/4）,tan(a-π/4)
tanπ/4=1
求tan（a+π/4）=(tana+tanπ/4)/(1-tana*tanπ/4)
=(tana+1)/(1-tana)
=-2
tan(a-π/4)=(tana-tanπ/4)/(1+tana*tanπ/4)
=(tana-1)/(1+tana)
=1/2
答
tan（a+π/4）=(tana+1)/(1-tana),=-2
tan（a-π/4）=(tana-1)/(1+tana),=1/2
答
tan(a+π/4)
=(tana+tan(π/4))/[1-tana *tan(π/4)]
=(3+1)/(1-3*1)
=-2
tan(a-π/4)
=(tana-tan(π/4))/[1+tana *tan(π/4)]
=(3-1)/(1+3)
=2/4
=1/2
不懂的欢迎追问,