a0a 只是得一條咋
第9條 =]
我唔明點做要解釋
=]最好就係用中文
http://i164.photobucket.com/albums/u4/ming21ki/IMG_0004-13.jpg
a0a 中4MATHS 只是得一條咋
2007-11-25 8:55 am
回答 (1)
2007-11-25 9:18 am
✔ 最佳答案
The area of rectangle PQRS=(2x+12)(4-x)
=-(2x+12)(x-4)
=-(2x^2+4x-48)
=-2x^2-4x+48
Let y cm^2 be the max.area of PQRS.
y=-2x^2-4x+48
=-2(x^2+2x+1)+2+48
=-2(x+1)^2+50
>=50
the max.area of PQRS is 50cm^2.
2007-11-25 02:24:55 補充：
唔係>=50係<=50
參考: MYSELF
收錄日期: 2021-04-14 00:07:34
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071125000051KK00319