A question about inequality~
2010-03-27 8:46 am
A farmer with 10000 meters of fencing wants to enclose a rectangular field and then divide it into two plots with a fence parallel to one of the sides. If the area cannot less than 2000m^2. What is the largest length of L can be?
回答 (1)
2010-03-27 7:39 pm
✔ 最佳答案
Let x be the length, y be the widthThen
x ≥ 0
y ≥ 0
3x + 2y ≤ 10000
xy ≥ 2000
圖片參考：http://imgcld.yimg.com/8/n/HA00532045/o/701003270005013873369810.jpg
Sub y = 2000/x
3x + 2(2000/x) = 10000
3x2 + 4000 = 10000x
3x2 – 10000x + 4000 = 0
x = 3333m or x = 0.4000m
(corr. to 4 sig. fig.)
So the largest length is 3333m.
收錄日期: 2021-04-24 23:21:54
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100327000051KK00050