Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 2 - Review - Modeling with Functions - Problems - Page 242: 21

Answer

(a ) 720000, see table below. (b) $A=-2x^2+2400x$ (c) $720000$

Work Step by Step

(a )Try values of $x=100,200,300,400,500,600, 700, 800, 900, 1000$, etc. as shown in the table. The maximum can be estimated to be 720000 when the short side $x$ is 600ft. (b) Use the figure in the problem, one side of the fence is $x$, the other side would be $2400-2x$ and the area can be expressed as $A=x(2400-2x)=-2x^2+2400x$ (c) The maximum of the above equation happens when $x=2400/4=600$ which gives an area of $y=720000$, and this value agrees with the result from (a).
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.