Y=X是斜率为45度=π/4角2a的终边与π/6关于Y=X对称,则2a-π/4=π/4-π/62a=(π/4+π/4-π/6)=π/3因为a ∈（-2π,2π）,2a ∈（-4π,4π）,所以在此区间内2a可以取值π/3-4π,π/3-2π,π/3,π/3+2π因此a=-11π/3或...