The base of an aquarium with given volume V is made of slate and the sides are made of glass. If the slate costs seven times as much (per unit area) as glass, use Lagrange multipliers to find the dimensions of the aquarium that minimize the cost of the materials. (Enter the dimensions as a comma separated list; Note that the variable volume is a capital V and must be entered as such, using the shift rather than caps-lock key)

Answers

Answer 1

Answer:

[tex]l = \sqrt[3]{\frac{2V}{7}}[/tex]     [tex]b = \sqrt[3]{\frac{2V}{7}}[/tex]       [tex]h = \sqrt[3]{\frac{49V}{4}}[/tex]

Step-by-step explanation:

Represent the volume of the box with V and the dimensions with l, b and h.

The volume (V) is:

[tex]V = l * b * h[/tex]

Make h the subject of the formula

[tex]h = \frac{V}{lb}[/tex]

The surface area (S) of the aquarium is:

[tex]S = lb + 2(lh + bh)[/tex]

Where lb represents the area of the base (i.e. slate):

The cost (C) of the surface area is:

[tex]C = 7 * lb + 1 * 2(lh + bh)[/tex]

[tex]C = 7lb + 2(lh + bh)[/tex]

[tex]C = 7lb + 2h(l + b)[/tex]

Substitute [tex]\frac{V}{lb}[/tex] for h in the above equation

[tex]C = 7lb + 2*\frac{V}{lb}(l + b)[/tex]

[tex]C = 7lb + \frac{2V}{lb}(l + b)[/tex]

[tex]C = 7lb + \frac{2V}{b} + \frac{2V}{l}[/tex]

Differentiate with respect to l and with respect to b

[tex]C_l=7b - \frac{2V}{l^2}[/tex] [tex]=0[/tex]

[tex]C_b=7l - \frac{2V}{b^2}[/tex] [tex]=0[/tex]

To solve for b and l, we equate both equations and set l to b (to minimize the cost)

[tex]7b - \frac{2V}{l^2}=7l - \frac{2V}{b^2}[/tex]

[tex]7l - \frac{2V}{l^2}=7b - \frac{2V}{b^2}[/tex]

By comparison:

[tex]l =b[/tex]

[tex]C_l=7b - \frac{2V}{l^2}[/tex] [tex]=0[/tex] becomes

[tex]7l - \frac{2V}{l^2}=0[/tex]

[tex]7l = \frac{2V}{l^2}[/tex]

Cross Multiply

[tex]7l^3 = 2V[/tex]

Solve for l

[tex]l^3 = \frac{2V}{7}[/tex]

[tex]l = \sqrt[3]{\frac{2V}{7}}[/tex]

Recall that: [tex]l =b[/tex]

[tex]b = \sqrt[3]{\frac{2V}{7}}[/tex]

Also recall that:

[tex]h = \frac{V}{lb}[/tex]

[tex]h = \frac{V}{\sqrt[3]{\frac{2V}{7}}*\sqrt[3]{\frac{2V}{7}}}[/tex]

[tex]h = \frac{V}{\sqrt[3]{\frac{4V^2}{49}}}[/tex]

Apply law of indices

[tex]h = \sqrt[3]{\frac{49V^3}{4V^2}}[/tex]

[tex]h = \sqrt[3]{\frac{49V}{4}}[/tex]

The dimension that minimizes the cost of material of the aquarium is:

[tex]l = \sqrt[3]{\frac{2V}{7}}[/tex]     [tex]b = \sqrt[3]{\frac{2V}{7}}[/tex]       [tex]h = \sqrt[3]{\frac{49V}{4}}[/tex]


Related Questions

40 of the cats at the pet store are black, which is 25% of all cats. How many cats are there at the pet store

Answers

Answer:

There are 160 cats at the store.

Step-by-step explanation:

There are 40 black cats, which is 25% of all the cats. You are trying to find all the cats at the store, or 100% of the cats at the store. So:

40 = 25%

40(4) = 25% (4)

160 = 100%

There are 160 cats at the store.

Answer:

160

Step-by-step explanation:

25%=1/4=0.25

=40×4

=160

jessica wondered if elementary school students tend to write more when they are given

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full question plsAnswer:

Step-by-step explanation:

40.1 =
С C
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0.1

Answers

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1.876

because I said it was

En una tienda de videojuegos venden, por la mañana, las 3/4 partes de los que tenían. Por la tarde vendieron 4/5 de los que le quedaban. Cuando cerró la tienda quedaron 200 videojuegos sin vender, ¿cuántos había al principio?, ¿cuántos vendieron por la tarde?

Answers

al principio había 10

y se vendieron por la tarde150

2 -7
-9
5
Given A=
and B-
6
1
-1
If X-A=B, what is X?
-2
O
7
0
-11
12
-2
-5
-7 -12
5
0
11-12

Answers

Answer:

it is b              furqufhrfhquh quf hqhf

Step-by-step explanation:bfygefy eyfeyfyewfyefwef eqf  

\fn qf7f

The value of the matrix X is X =  [tex]\left[\begin{array}{ccc}-7&-2\\7&0\\\end{array}\right][/tex].

What are Matrices?

Matrices are a set of numbers arranged in such a way that the numbers are arranged in rows and columns.

Each number is called element in a matrix.

Given are two matrices.

A = [tex]\left[\begin{array}{ccc}2&-7\\6&1\\\end{array}\right][/tex] and B = [tex]\left[\begin{array}{ccc}-9&5\\1&-1\\\end{array}\right][/tex]

We have given that, a matrix X exists such that,

X - A = B

We can rearrange this as,

X = A + B

Adding the two matrices,

The entries will be,

2 - 9 = -7

-7 + 5 = -2

6 + 1 = 7

1 - 1 = 0

X =  [tex]\left[\begin{array}{ccc}-7&-2\\7&0\\\end{array}\right][/tex]

Hence the X is option A.

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Four points A, B, C, and d are on a number line, in some order, so that AB=1, BC=2, CD=3, and DA=4. Which two points are farthest away from each other?

Answers

Answer: B or C sorry if its wrong

Step-by-step explanation: have a nice day

Which pair of angles are complementary but not adjacent?
1
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5
3
4
+
0 21 and 25
0 21 and 23
0 24 and 21
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Answers

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Step-by-step explanation:

I got it right on edge 2021

Answer:

1 and 3

Step-by-step explanation:

carry out the following divisions.​

Answers

Answer:

9a²b²c²

Step-by-step explanation:

72a³b⁴c⁵ / 8ab²c³

= 9a²b²c²

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Answers

Answer:

x = -8

Step-by-step explanation:

If the line is parallel to the y axis, that means it will be a vertical line.

Vertical lines have an equation of x = , because the line will only go through one x value.

They also will not have a slope, because their slope is undefined.

So, the correct answer is x = -8

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The volume would be 768 cm^3

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Answers

Answer:

ur answer is right it is 9

Step-by-step explanation:

NOTE: divide the number 36 with 4 and u will get 9

GOOD JOB

Please mark as brainliest

Have a great day, be safe and healthy

Thank u  

XD

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Answers

Answer:

x= -8

Step-by-step explanation:

Move the terms

Calculate: -x=12-4 = -x=8

Change the signs

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Answers

Answer:

? = 5n + 6

Explanation:

Answer:

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Answers

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Answers

Answer:

Step-by-step explanation:

18). 3x + 2 ÷ 3x = [tex]\frac{2}{3x}[/tex]

     Since, 3x + 2 ÷ 3x = 3x + [tex]\frac{2}{3x}[/tex]

      Therefore, right hand side of the equation will be = 3x + [tex]\frac{2}{3x}[/tex]

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       Since, [tex]\frac{4x+3}{3}=\frac{4x}{3}+\frac{3}{3}[/tex]

                            = [tex]\frac{4}{3}x+1[/tex]

Therefore, right hand side of the equation should be [tex]\frac{4}{3}x+1[/tex].

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Answers

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3.

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Story Problem:
Avery purchased 4 tacos and 2 burritos and her total cost was $21. Sasha purchased 4 tacos and 3 burritos
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Answers

Answer:

Step-by-step explanation:

Let tacos be x and burritos be y

So, Avery purchased 4x+2y = 21

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Solving the 2 eqns:

4x+2y=21

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Answers

Answer:

A I think

Step-by-step explanation:

because if you add them up.

Answer:

Aprox. 216 days

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If i helped, a brainliest answer would be greatly appreciated!

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Step-by-step explanation:

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Answer:

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The equation of the line of best fit of a scatter plot is y = 8x - 1. What is the slope of
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Answers

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Step-by-step explanation:

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Answers

Answer:

[tex]\%Change = -40\%[/tex]

Step-by-step explanation:

Given

[tex]Initial = 6.5kg[/tex]

[tex]Final = 3.9kg[/tex]

Required

Determine the percentage change --- Missing from the question

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[tex]\%Change = \frac{Final - Initial}{Initial} * 100\%[/tex]

[tex]\%Change = \frac{3.9kg - 6.5kg}{6.5kg} * 100\%[/tex]

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Answers

Answer:

YES SIR OR I MEANT YES MAM

how many 5 digits numbers can be created using digits 1,2,3,7, and 6 without repeating any digits within that 5-digit number?

Answers

There are 5 numbers that can be used.

The first digit can be 1 of 5

The second digit can be 1 of 4

The third digit is 1 of 3

The fourth digit is 1 of 2

The fifth digit is 1 of 1

Total digits that can be created = 5 x 4 x 3 x 2 x1 = 120

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bsjsudhdhehe​

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3x + 2y = 30
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Answers

Answer:

D

Step-by-step explanation:

Answer:

I think this one is C

Step-by-step explanation:

It seems like its counting by 5's and the answer to the first equation

Hey guys I need help asap

A salesman earns 15% commission on each household appliance he sells. If he sells 6 toasters at $32 each, what is the commission that he earned?

Answers

Answer:

$28.8

Step-by-step explanation:

6x32=192

15% of 192 is 28.8

2X-5<9 solve inequality

Answers

Step-by-step explanation:

2x<9+5

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2x/2<14/2

x<7

Answer:

[tex]\boxed {\boxed {\sf x <7}}[/tex]

Step-by-step explanation:

To solve the inequality you must isolate the variable, which is x.

[tex]2x-5 < 9[/tex]

5 is being subtracted from 2x. The inverse of subtraction is addition, so add 5 to both sides of the equation.

[tex]2x-5+5 < 9+5[/tex]

[tex]2x < 14[/tex]

x is being multiplied by 2. The inverse of multiplication is division, so divide both sides by 2.

[tex]\frac {2x}{2} < \frac {14}{2}[/tex]

[tex]x <7[/tex]

The solution to this inequality is x <7

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