# Find rectangle with largest area

• Jun 21st 2008, 03:11 PM
PensFan10
Find rectangle with largest area
I attempted to solve this problem. I just want to make sure that I did it properly.

The parabola is y=8-x^2
Rectangle = 2x(8-x^2)
=16-6x^2 (i got this by first distributing 2x then finding the derivative)
X= Sqrt(8/3)

Since the base is 2x, the base of this rect. would be 2Sqrt(8/3)
then since y is a f(x). I get 16/3

The dimensions of my rectangle would be H= 16/3 and L = 2Sqrt(8/3)
My area would be 17.42

Thank you!
• Jun 21st 2008, 05:43 PM
topsquark
Quote:

Originally Posted by PensFan10
I attempted to solve this problem. I just want to make sure that I did it properly.

The parabola is y=8-x^2
Rectangle = 2x(8-x^2)
=16-6x^2 (i got this by first distributing 2x then finding the derivative)
X= Sqrt(8/3)

Since the base is 2x, the base of this rect. would be 2Sqrt(8/3)
then since y is a f(x). I get 16/3

The dimensions of my rectangle would be H= 16/3 and L = 2Sqrt(8/3)
My area would be 17.42

Thank you!

You have it done correctly, but before you hand something like this in for credit PLEASE organize your work more clearly!

-Dan
• Jun 21st 2008, 06:22 PM
PensFan10
Okay thanks. I will see what I can do about the organization problem :P