數學難題 (超急)(15分)

2007-10-26 5:10 pm
1. A manufacturer of lighting fixtures has daily production costs modeled by
y = 0.25x^2 - 10x + 800

where y is the total cost in dollars and x is the number of fixtures produced.

a. Sketch the graph of the model. Label the vertex.
b. What is the minimum daily production cost, y?
c. How many fixtures should be produced each day to yield a minimum cost?
更新1:

仲有一條,我其實都識識地的,不過計到出來唔知岩唔岩,所以想再問下 Figure: http://img.photobucket.com/albums/v439/pd3333/ADVBP%20Photo/tri.jpg a. Find x b. Find the sum of 3x and 4x c. Find difference between 3x+4x and 35

回答 (4)

2007-10-26 5:43 pm
✔ 最佳答案
y = 0.25x^2 - 10x + 800
= 0.25(x^2 - 40x) + 800
= 0.25(x^2 - 40x + 400) - 100 + 800
= 0.25(x - 20)^2 + 700
a. Sketch the graph of the model. Label the vertex.
vertex = (20, 700)
open upwards because a = 0.25 > 0
y - intercept = 800
you can plot it easily from this three conditions
-------------------------------------------------------------------
b. What is the minimum daily production cost, y?
minimum daily production cost = 700
-------------------------------------------------------------------
c. How many fixtures should be produced each day to yield a minimum cost?
no. of fixtures produced = 20

2007-10-26 09:44:24 補充:
上面位係咪做錯左??
2007-10-27 2:27 am
Ans:20
2007-10-26 6:50 pm
我用excel 做左, 依家send比你

2007-10-27 09:33:19 補充:
用左yahoo mail比你
2007-10-26 5:20 pm
a. vertex = 20
b. when x=0 => y=800
c. average cost per unit = y/x => At x = 56, min cost ~ 18.29

2007-10-26 09:26:32 補充:
Can use Gnuplot for (a)http://www.gnuplot.info/


收錄日期: 2021-04-23 20:08:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071026000051KK00565

檢視 Wayback Machine 備份