Try the fastest way to create flashcards
Question

From a 12-cm by a 12-cm piece of cardboard, square corners are cut out so that the sides can be folded up to make a box.

a) Express the volume of the box as a function of the side x, in centimeters, of a cut-out square.

b) Find the domain of the function.

c) Graph the function with a graphing calculator.

d) What dimensions yield the maximum volume?

Solution

Verified

a)

The volume of the box is:

V=lwhV=lwh

Since l=122xl=12-2x, w=122xw=12-2x, and h=xh=x, the volume is:

V(x)=(122x)(122x)(x)V(x)=(12-2x)(12-2x)(x)

V(x)=(14448x+4x2)(x)V(x)=(144-48x+4x^2) (x)

V(x)=144x48x2+4x3V(x)= 144x-48x^2+4x^3

or

V(x)=4x348x2+144x\color{#c34632}V(x)= 4x^3-48x^2+144x

b)

Each dimension of the box must be greater than 0 so:

122x>0x<612-2x>0\to x<6

122x>0x<612-2x>0\to x<6

x>0x>0

So, the domain is:

0<x<6\color{#c34632}0<x<6

c)

Graph the function from (a) using the domain from part (b): Slader d)

Using the maximum feature, the maximum point is (2,128)(2,128). Slader So, the volume is maximum at x=2x=2 and the dimensions are:

length=122x=122(2)=8 cmwidth=122x=122(2)=8 cmheight=x=2 cm\begin{aligned} \text{length}&=12-2x=12-2(2)=\color{#c34632}8\text{ cm}\\ \text{width}&=12-2x=12-2(2)=\color{#c34632}8\text{ cm}\\ \text{height}&=x=\color{#c34632}2\text{ cm} \end{aligned}

Create a free account to view solutions

Create a free account to view solutions

Recommended textbook solutions

Precalculus 2nd Edition by Carter, Cuevas, Day, Malloy

Precalculus

2nd EditionISBN: 9780076602186Carter, Cuevas, Day, Malloy
8,886 solutions
Nelson Functions 11 1st Edition by Chris Kirkpatrick, Marian Small

Nelson Functions 11

1st EditionISBN: 9780176332037Chris Kirkpatrick, Marian Small
1,275 solutions
Precalculus with Limits 3rd Edition by Larson

Precalculus with Limits

3rd EditionISBN: 9781133962885 (2 more)Larson
11,142 solutions
Precalculus: Mathematics for Calculus 7th Edition by Lothar Redlin, Stewart, Watson

Precalculus: Mathematics for Calculus

7th EditionISBN: 9781305071759 (6 more)Lothar Redlin, Stewart, Watson
9,727 solutions

More related questions

1/4

1/7