Posted by **Bob** on Thursday, November 4, 2010 at 9:13pm.

A square-based, box-shaped shipping crate is designed to have a volume of 16ft^3. The material used to make the base costs twice as much (per ft^2) as the material in the sides, and the material used to make the top costs half as much (per ft^2) as the material in the sides. What are the dimensions of the crate that minimize the cost of materials?

- calculus -
**MathMate**, Thursday, November 4, 2010 at 10:04pm
Since the base is square, and the volume is constant, there is only one variable, such as the side of the base, x.

The height is therefore h=V/x².

The cost of the base is

Cb=C1*x²

Cost of the four sides is

Cs=C2*(4x*h)

Cost of the cover is

Cc=C3*x²

Total cost as a function of x

C(x)= C1*x²+C2*(4x*V/x²)+C3*x²

=(C1+C3)x²+ 4C2*V/x

Differentiate with respect to x and equation f'(x) to zero. Solve for x0 where the cost is maximum/minimum.

To find out if f(x0) is a maximum or minimum, calculate the second derivative and evaluate f"(x0). If f"(x0)>0, f(x0) is a minimum. If f"(x0)<0, f(x0) is a maximum.

- calculus -
**joe smith**, Friday, November 9, 2012 at 11:59am
45

## Answer this Question

## Related Questions

- Algebra - 4. A shipping crate has a square base with sides of length x feet, and...
- calculus - a rectangular box is to have a square base and a volume of 20 ft ...
- calculus - A rectangular box is to be constructed from two different materials. ...
- Calculus - A rectangular box is to have a square base and a volume of 20 ft3. If...
- Calculus - A company is designing shipping crates and wants the volume of each ...
- Calculus - A rectangular storage container with an open top is to have a volume ...
- Calculus - A rectangular box is to have a square base and a volume of 20 ft3. ...
- calculus - A rectangular box is to have a square base and a volume of 50 ft3. ...
- calculus - A rectangular box is to have a square base and a volume of 50 ft3. ...
- calculus - A rectangular box is to have a square base and a volume of 50 ft3. ...

More Related Questions