What is the maximum volume in cubic inches of an open box to be made from a 16-inch by 30-inch piece of cardboard by cutting out squares of equal sides from the four corners and bending up the sides? Your work must include a statement of the function and its derivative. Give one decimal place in your final answer.

My answer: Is this correct?
f(x)=4x^3-92x^2+480x=Volume
f'(x)=12x^2-184x+480

x=10/3
x=12

Max volume comes from 10/3 length cubes, and the volume will be 725.9 in^3

1 answer

all looks good

Also the reason we reject x = 12 ...
one of the sides would be (16-24) which is negative.