已知tan(-a-4π/3)=-5,则tan（π/3+a）的值为
问题描述：
已知tan(-a-4π/3)=-5,则tan（π/3+a）的值为
答
解
tan(-a-4π/3)
=tan[-(a+4π/3)]
=-tan(a+4π/3)
=-tan(a+π+π/3)
=-tan(a+π/3)
=-5
∴tan(a+π/3)=5