已知线段AB,点C是线段AB的黄金分割点,且AC>BC,若AB=2cm,则BC= cm

由题设知：AC/CB=(√5+1)/2. (∵AC>BC),
(AC+CB)/CB=(√5+1+2)/2,
AB/BC=(3+√5)/2.
2/BC=(3+√5)/2.
BC=4/(3+√5).
=4(3-√5)/[(3+√5)(3-√5)].
=4(3-√5)/[(3^2-(√5)^2].
=4(3-√5)/(9-5).
=4(3-√5)/4.
∴BC=3-√5..应该是你做的结果对.