Thursday, January 21, 2010

Rectangle and Parabola

Find the dimensions of a rectangle of maximum area, whose base lies on the x axis, and whose upper vertices lie on the parabola y = 12 - x^2. And what is the maximum area?

3 Comments:

Blogger Chris said...

32

January 21, 2010 10:36 PM  
Blogger Chris said...

Let (x,y) be the coordinates of the top right corner of the rectangle.

Are of rectangle = 2xy = 2x(12 - x²)
A = 24x - 2x³

dA/dx = 24 - 6x² = 0 => x = 2
So Amax = 48 - 16 = 32

January 21, 2010 11:10 PM  
Anonymous Zaux said...

Chris,
32 it is

January 22, 2010 5:59 AM  

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