# Thread: Need help with optimization problem

1. ## Need help with optimization problem

Hello everyone

If anyone would want to tell me how to do this that would be great.

4.) A rectangle is inscribed above the x-axis inside the parabola y = a^2 - x^2. find the area of the largest possible rectangle.

the constant 'a' gives me problems here. The pic at the bottom is a diagram of #4.

2. Just in case a picture helps...

(A = area)

Spoiler:

_________________________________________
Don't integrate - balloontegrate!

Balloon Calculus; standard integrals, derivatives and methods

Balloon Calculus Drawing with LaTeX and Asymptote!

3. yes yes i have gotten that far but i dont know how to differentiate with 'a' in there. could i maybe take it out then differentiate? then account for it later somehow? idk...

4. Originally Posted by jsel21
yes yes i have gotten that far but i dont know how to differentiate with 'a' in there. could i maybe take it out then differentiate? then account for it later somehow? idk...
Yes, I thought that was the problem - see the spoiler pic, which I got a bit tied up with, sorry. The point is you just treat a as a constant (a number), because it is, for the problem in hand.

5. thanks so much.. i should have known that!