在同一平面内有2011条直线a1,a2,a3...,a2011,a1⊥a2,a2//a3,a3⊥a4,a4//a5,那么

a1⊥a2,a2‖a3→→a1⊥a3
a1⊥a3,a3⊥a4→→a1‖a4
a1‖a4,a4‖a5→→a1‖a5
a1‖a5,a5⊥a6→→a1⊥a6
a1⊥a6,a6‖a7→→a1⊥a7
a1⊥a7,a7⊥a8→→a1‖a8
a1‖a8,a8‖a9→→a1‖a9
.
.
看到规律了吧
4个循环一次
所以
2011/4=502····3
是垂直