Monday, December 04, 2006

Lesson 3.1 Quadratic Functions and Models
Discuss Problems 76 and 78 on page 192

1 Comments:

Anonymous Anonymous said...

3.1 #76 ) 76. A farmer with 10,000 meters of fencing wants to enclose a rectangular field and then divide it into two plots with a fence prallel to one of the sides (see the figure on pg. 192). What is the largest area that can be enclosed???

The wording of this problem confused me. I did not understand what the question was asking. I took it as the area of both parts totaled. First, you know that 10,000=3x+2y. You also know that the area is still going to be = to xy (Area=xy). To express the area in terms of a single variable, you must solve the first equation for y and substitute the answer into the A= xy equation.

5000-(3/2)x=y
A=(x)(5000-(3/2)x)
A= (-3/2)x²+ 5000x
Now that you have a quadratic function, you can find the maximum point, which is the maximum value of A, by finding -b/2a. ( This is where the value occurs at, not the actual value.)

= 5000/3

The maximum value = A = (-3/2)(5000/3)²+ 5000(5000/3)

= 4166666.667


Taylor McClanahan

5:22 PM

 

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