Re: [中學] 想請問一題拋物線問題
由定義知, 若有拋物線符合此條件
其焦點距 (3,3) 為 3, 距 (-3,4) 為 4
而此兩點距離為 √(6^2 + 1^2) = √37
易知 3 + 4 > √37，因此此兩點和焦點可以形成三角形，即存在焦點符合距離條件
有焦點有準線就能畫拋物線了
(同時亦知符合條件的拋物線共有兩條)
--
'You've sort of made up for it tonight,' said Harry. 'Getting the
sword. Finishing the Horcrux. Saving my life.'
'That makes me sound a lot cooler then I was,' Ron mumbled.
'Stuff like that always sounds cooler then it really was,' said
Harry. 'I've been trying to tell you that for years.'
-- Harry Potter and the Deathly Hollows, P.308
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 123.195.39.85
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1452178070.A.3D1.html
討論串 (同標題文章)
