A:(11,25)
B:(12,22)
C:(12,17)
D:(14,20)
My English teacher _______ Ms Black. ()
The students their pens when the teacher told them to stop writing.
定义:如图1,点C在线段AB上,若满足AC2=BC•AB,则称点C为线段AB的黄金分割点.如图2,△ABC中,AB=AC=1,∠A=36°,BD平分∠ABC交AC于点D.
(1)求证:点D是线段AC的黄金分割点;
(2)求出线段AD的长.