A simple question I'd like to verify the answer to:

An open box is to be made from a square piece of aluminium, 3cm on a side, by cutting equal squares from each corner and then folding up the sides. Determine the dimensions of the box that will have the largest volume.

The text gave a answer of 2cm x 2cm x 0.5cm.
However, I got 2cm x 2cm x 1cm. Now I'm pretty sure that I'm correct, but I haven't done optimization problems for a while. A little verification would be nice, lol.

Question

A simple question I'd like to verify the answer to:

An open box is to be made from a square piece of aluminium, 3cm on a side, by cutting equal squares from each corner and then folding up the sides. Determine the dimensions of the box that will have the largest volume.

The text gave a answer of 2cm x 2cm x 0.5cm.
However, I got 2cm x 2cm x 1cm. Now I'm pretty sure that I'm correct, but I haven't done optimization problems for a while. A little verification would be nice, lol.