A 1,000 gallon pool (no top) with a rectangular base will be constructed such that the length of the base is twice the width. Find the dimensions (length, width, and height) of the pool that minimize the amount of material needed to construct it.

W = 4.646 ft

L = 9.292 ft

H = 3.097 ft

Step-by-step explanation:

Let's say the L is the length, W is the width, and H is the height.

The volume of the pool is:

V = LWH

The area of the pool is:

A = LW + 2LH + 2WH

L = 2W, so substituting:

V = (2W)WH

V = 2W²H

A = (2W)W + 2(2W)H + 2WH

A = 2W² + 4WH + 2WH

A = 2W² + 6WH

Solving for H in the first equation and substituting into the second:

H = V/(2W²)

A = 2W² + 3V/W

Find dA/dW and set to 0.

dA/dW = 4W − 3V/W²

0 = 4W − 3V/W²

4W = 3V/W²

4W³ = 3V

W = ∛(¾V)

V = 1000 gallons or 133.7 ft³.

W = ∛(¾(133.7 ft³))

W = 4.646 ft

So L = 9.292 ft and H = 3.097 ft.

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explanation

the graph has a slope of 1/3 because each time you move up 1, you go to the right 3. so, slope = rise/run = 1/3. we can cross choice a off the list since we want a slope of 3, rather than 1/3.

the first table shown has a slope of -3. this is because the rise is -6 and the run is 2, so slope = rise/run = -6/2 = -3. note how x increases by 2 each time (run) and y drops by 6 each time (rise). choice b can be eliminated.

the second table has a slope of 3. each time x goes up by 1, the y values increase by 3. slope = rise/run = 3/1 = 3. alternatively you can use the slope formula to prove that the slope is 3 here. use any two rows of values to generate the two points. choice c is one of the answers

the third table also has a slope of 3. let's use the slope formula to prove as such. i'm going to use the first two rows of the table. so i'll use the two points (2,1) and (5,10)

m = slope

m = (y2-y1)/(x2-x1)

m = (10-1)/(5-2)

m = 9/3

m = 3 so we get a slope of 3

choice d is the other answer

let m = monomial

let t = trinomial

so, m times t = t.

monomial times a trinomial = another trinomial.