General formula for maximum volume when cutting a box with L = 1.414w

[Shakattack12]

Homework Statement

A box is given with a L = 1.414w and W = w and a cut size = x. Find the general formula for the maximum volume.

Homework Equations

L = 1.414w - 2x
W = w - 2x
H = x

The Attempt at a Solution

V = x(1.414w - 2x)(w - 2x)
V = 4x³ - 4.818x²w + 1.414w²
Apparently this isn't the general formula for max volume, so someone please help.

 

[Shakattack12]

Never mind guys. I figured it out.