✔ 最佳答案
圖片參考:
https://s.yimg.com/lo/api/res/1.2//YXBwaWQ9dHdhbnN3ZXJzO3E9ODU-/http://oi61.tinypic.com/iokjme.jpg
The equation of AB is y = 3.
A , B are common points of y = - 3(x - 6)² + 15 and y = 3.
So a , b are roots of 3 = - 3(x - 6)² + 15
(x - 6)² - 4 = 0
(x - 6 - 2)(x - 6 + 2) = 0
(x - 8)(x - 4) = 0
a < b so a = 4 , b = 8 , the distance between A and B = 8 - 4 = 4.
2015-06-12 13:55:20 補充:
因為圖中沒有畫出直線AB,所以你唔識代入y,
如果有畫出直線AB你可能就會識,這個故事提醒你一個道理 :
有D野雖然係識,但是識並不代表能於適當時侯自覺地運用出來。
2015-06-12 15:30:29 補充:
目前只能肯定過去是可貼圖的。
2015-06-12 17:28:51 補充:
是個別版塊的題數不對,還是題數對但計錯數?