题目内容：

将线段AB延长至C,使BC=(1/3)AB,延长BC至D,使CD=(1/3)BC,延长CD至E,使DE=(1/3)CD,
将线段AB延长至C,使BC=(1/3)AB,延长BC至D,使CD=(1/3)BC,延长CD至E,使DE=(1/3)CD,若AE=8cm,求AB的长