題目比咗條式我要我plot graph, 條式係咁:
U=-x2+20x
個答案係將佢轉做
=-(x-10)2+100
有冇人可以教我點轉呢條式
唔好意思我數學白痴...
更新1:
第一個x2個2係square 下面括號後都係
經濟數學(utility)
2010-01-08 12:43 am
我想問一條數
題目比咗條式我要我plot graph, 條式係咁:
U=-x2+20x
個答案係將佢轉做
=-(x-10)2+100
有冇人可以教我點轉呢條式
唔好意思我數學白痴...
題目比咗條式我要我plot graph, 條式係咁:
U=-x2+20x
個答案係將佢轉做
=-(x-10)2+100
有冇人可以教我點轉呢條式
唔好意思我數學白痴...
回答 (1)
2010-01-08 1:00 am
✔ 最佳答案
U = - x^2 + 20x= - (x^2 - 20x)
= - (x^2 - 2(10)x + 10^2 - 10^2 ) ...........using a^2 - 2ab + b^2
= - [ (x - 10)^2 - 10^2 ].........................= (a - b)^2 , a=x and b=10 here.
= - (x - 10)^2 + 10^2
= - (x - 10)^2 + 100
收錄日期: 2021-04-21 22:10:08
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100107000051KK00799