SOLUTION: How Would I create a Real Life Example Involving Polynomials?

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Question 112462: How Would I create a Real Life Example Involving Polynomials?
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!
Let's say you have a square piece of sheet aluminum that is 12 inches on each side. You want to cut a square of dimension x by x from each corner of the sheet and then fold the sides up to make an open topped box. What dimension should you select for x so that box you make has the maximum possible volume?


If the original sheet of metal is 12" by 12", and you cut an x by x square from each corner, the dimensions of the bottom of the box would then be 12 - 2x inches. Then the volume with respect to the x dimension of the box would be V%28x%29=%2812-2x%29%2812-2x%29x.

First, let's test a couple of values to see if it makes any difference. Let's try x = 1. x = 1 means that our box would be 10 by 10 on the bottom and 1 inch tall for a total volume of 100 cubic inches. Let's try x = 3. x = 3 means that the box would be 6 by 6 on the bottom and 3 inches tall, 6 X 6 X 3 = 108 cubic inches. So clearly the selected value for x makes a difference in the volume.

V%28x%29=4x%5E3-48x%5E2%2B144x is the polynomial function, and the real life problem would be to find the value of x that makes the volume a maximum.

graph%28400%2C400%2C-1%2C12%2C-20%2C150%2C4x%5E3-48x%5E2%2B144x%29

The graph illustrates the situation. Values for x larger than 6 don't have any application because if x were 6 or larger, there wouldn't be any metal left to make a box. So the interval of interest is 0%3Cx%3C6

Ok. Extra credit. It looks like the x value at the maximum is about 2. What is the volume of the box if x = 2?