Optimization - area of rectangle

look416
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Homework Statement


If the perimeter of a rectangle is fixed in length, show that the area of the rectangle is greatest when it is square


Homework Equations





The Attempt at a Solution


if the perimeter is fixed in length, then 2x + 2y = c
then no idea to continue from there
 
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Ok so far. Now you want to maximize x*y, right? Eliminate one of the variables using the perimeter condition and differentiate, etc.
 


look416 said:

The Attempt at a Solution


if the perimeter is fixed in length, then 2x + 2y = c
then no idea to continue from there

So what is the area A in terms of x and c?
 

Thread 'Finding the nth roots of a complex number'

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