tan(π/7+α)=5,则tan(6π/7-α)=

问题描述:

tan(π/7+α)=5,则tan(6π/7-α)=

tanx为奇函数
因为tan(π/7+α)=5,则tan(-π/7-α)=-5
而tan(6π/7-α)=tan(-π/7-α+π),tan(π+x)=tanx
于是tan(6π/7-α)=-5