[請益] 國二數學一題
想請教各位大大的這題是國二的題目:
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直角座標平面上兩點A(3,4)、B(7,-2),若P為X軸上的任一點,則PA-PB的最大值為多少?
這題是選擇題 有四個答案: 2√13、2√11、2√7、2√5 答案卷上給的是2√5
這題我的想法是:
1. P的座標是(x.0)
2. √(x-3)^2+16 - √(x-7)^2+4 然後求出他的最大值
然後我就死在這裡了 因為接下來的計算過程就國二學生而言 應該算是過難
請問這題題目有沒有問題呢? 或是有沒有更好的想法呢? 謝謝!!
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◆ From: 175.181.207.10
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※ 編輯: Tsumugi 來自: 175.181.207.10 (05/29 15:40)
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