190k views
0 votes
The side length of a rectangular box with a square base is increasing at the rate of 2 ft/sec, while the height is decreasing at the rate of 2 ft/sec. At what rate is the volume of the box changing when the side length is 10 ft and the height is 12 ft? Remember to use the product rule when you find the expression for dV/dt.

680 ft3/sec
40 ft3/sec
-280 ft3/sec
280 ft3/sec

User Mojoken
by
6.9k points

1 Answer

3 votes

Answer:

Therefore, the rate of change of the volume of the box when the side length is 10 ft and the height is 12 ft is 680 ft^3/sec.

Explanation:

I'd be happy to explain the solution step by step!

We want to find the rate of change of the volume of a rectangular box with a square base, where the side length is increasing at the rate of 2 ft/sec and the height is decreasing at the rate of 2 ft/sec. We are given that the side length is 10 ft and the height is 12 ft.

Step 1: Write the formula for the volume of the rectangular box

The volume V of a rectangular box with a square base is given by:

V = (side length)^2 x height

Step 2: Take the derivative of the volume formula with respect to time

We want to find the rate of change of the volume with respect to time, so we need to take the derivative of the volume formula with respect to time t. We will use the product rule to differentiate the formula:

dV/dt = 2 x (side length) x (d(side length)/dt) x height + (side length)^2 x (d height/dt)

The first term in the expression represents the rate of change of the volume due to the change in the side length, and the second term represents the rate of change of the volume due to the change in the height.

Step 3: Substitute the given values into the derivative formula

We are given that the side length is increasing at the rate of 2 ft/sec and the height is decreasing at the rate of 2 ft/sec, and that the side length is 10 ft and the height is 12 ft. Substituting these values into the derivative formula, we get:

dV/dt = 2 x 10 x 2 x 12 + 10^2 x (-2)

Simplifying this expression, we get:

dV/dt = 680 ft^3/sec

Therefore, the rate of change of the volume of the box when the side length is 10 ft and the height is 12 ft is 680 ft^3/sec.

User RuudVanNistelrooy
by
7.5k points