The quantity to be maximized - the dependent variable- is the volume
V of the box to be constructed. The shape and thus the volume of the box
are determined by the length x of the edge of each corner square removed.
Hence, X is the independent variable.
To write the volume V as a function of X, we note that the base will measure
(15 - 2x) inches by (25 - 2x) inches and the height is x giving:
Step 2: Express the dependent variable as a function of the independant
variable:
Step 3: Apply Calculus to find the critical points:
Step 4: Identify the extrema:
Step 5: Answer the question posed in the problem:
Question : The maximum volume of the box occurs when x (the height)
= 3.9. This yields a volume of : 482.976 cubic inches