線段ab=1,ac=根號(hào)5-1＞1
ac＞ab
∴c不會(huì)是線段ab上一點(diǎn),應(yīng)該是線段ab延長線上一點(diǎn)
bc=ac-1=根號(hào)5-1-根號(hào)5-2
ac/bc = (根號(hào)5-1)/(根號(hào)5-2）
= (根號(hào)5-1)(根號(hào)5+2)/{(根號(hào)5-2)(根號(hào)5+2)}
=3+根號(hào)5