A smokestack deposits soot on the ground with a concentration inversely proportional to the square of the distance from the stack. With two smokestacks d miles apart, the concentration of the combined deposits on the line joining them, at a distance x from one stack, is given by:
[tex]S=\frac{c}{x^2} +\frac{k}{(d-x)^2}[/tex]
where c and k are positive constants which depend on the quantity of smoke each stack is emitting. If k=8c, find the point on the line joining the stacks where the concentration of the deposit is a minimum. xmin= ? miles

Answers

Answer 1

Answer:

  d/3

Step-by-step explanation:

For k = 8c, the concentration is ...

  S = c/x^2 + 8c/(d -x)^2

The minimum of the function will be found where its derivative is zero. The derivative with respect to x is ...

  S' = -2c/x^3 +(-2)(8c)(-x)/(d -x)^3

We are interested in the value of x that makes this zero.

  0 = -2c/x^3 +16c/(d -x)^3 . . . . . simplify slightly, set S'=0

  0 = (-2(d -x)^3 +16x^3)/(x(d -x))^3 . . . . . combine terms, divide by c

  0 = d^3 -3d^2x +3dx^2 -x^3 -8x^3 . . . . multiply by (x(d-x))^3/(-2)

  9x^3 -3dx^2 +3d^2x -d^3 = 0 . . . . . simplified cubic

Factoring by grouping, we have ...

  (9x^3 -3dx^2) +(3d^2x -d^3) = 0

  3x^2(3x -d) +d^2(3x -d) = 0

  (3x^2 +d^2)(3x -d) = 0

The solution will be found where the second of these factors is zero:

  3x -d = 0

  x = d/3

The concentration of the deposit is a minimum at x = d/3 miles.

_____

The graph shows the minimum is x = 1/3 when d = 1.

A Smokestack Deposits Soot On The Ground With A Concentration Inversely Proportional To The Square Of

Related Questions

If x= - 2 is a solution to the equation f(x) = g(x), which one of these statements must be true?
• The graphs of f and g intersect each other at x = -2
• The graphs of f and g intersect each other at x = 2
• The graphs of f and g intersect the x-axis at -2
• The graphs of f and g intersect at the y-axis at -2

Answers

Answer:

The graphs of f and g intersect eachother at x = -2

Step-by-step explanation:

A solution to a system of equations or functions is the intersection point of them

factorize 4c−28 help

Answers

C = 7
All you do is put a zero at the end after the equal sign then make -28 positive 28 on the right side and replace it from zero then divide 4 on both sides and the answer is 7

__% of 4 is 7
hellpp

Answers

Answer:

175 %

Step-by-step explanation:

x % of 4 = 7

[tex]\dfrac{x}{100}*4 = 7\\\\\\x = 7*\dfrac{100}{4}\\\\x = 7*25\\\\x = 175[/tex]

(1,-1) (5,-7 find the slope

Answers

Answer:

m=-2

Step-by-step explanation:

m=-8/5-(1)

m=-8/4

divided -8 by 4

m=-2

Answer:

m=-2

Step-by-step explanation:

Please answer
It’s Pythagoras btw
ASAP

Answers

Answer:

X=11.979425

Step-by-step explanation:

Divide 7.3 and 5.5 which gives you 1.327272… Then, divide 15.9 by 1.3272727

what is x(14+2)5 please help me​

Answers

Answer: 80x

Step-by-step explanation:

1. add the numbers 14+2=16 (=x(16)(5)_)

2. Multiply the numbers 16(5) = 80 (=X(80) = 80X)

5 times the difference of a number and 2

Answers

Answer: 3.3

Step-by-step explanation: 5 divided by 3 x 2 = 3.3

help me or no branlest​

Answers

Answer:

48 * 70% or use 48 * 0.7

How many different 5-digit PIN codes are there that only include the digits 6, 2, 5, 4, 8 and 7?

Answers

Answer:

First, there are NO 5-digit pin codes that include the digits 7, 2, 4, 6, 9, and 3. But, there are 720 pin codes that include 5 out of the 6 digits.

pls Round 2.382 to the nearest hundred

Answers

If 2.383 is rounded to the nearest hundred the answer is 2.38

[tex]\huge\bold\blue{2.38}[/tex]

Explanation:

2 - ones

. - decimal point

3 - tenths

8 - hundredths

2 - thousandths

8 is the digit in the hundredths place

look at the number on its right (which is 2)

if: < 5, just copy the number until the nearest hundredths.

if: > or = 5, add 1 to the hundredths then copy the number until the nearest hundredths

I need help with this question

Answers

Answer:

make the image bigger then I will answer

Step-by-step explanation:

My little sister need help with this problem. Annabelle arranged her 42 building blocks into 3 rows of 14 blocks. Then, she rearranged them into 6 rows of 7 blocks. What two other factor pairs could Annabelle use to help her rearrange the blocks again?
Explain your answer using complete sentences.

Answers

Annabelle could arrange her blocks in one row of 42 building blocks as 1 times 42 = 42.

She could also arrange her blocks in 2 rows of 21 blocks because 2 times 21 is also 42.

Answer:

21 rows and two Blocks

1 row 42 Blocks

Step-by-step explanation:

Number of blocks with Annabelle = 42

First arrangement = 3 rows 14 blocks

Second arrangement = 6 rows 7 blocks

Solution

The other two factor pairs that could be used to rearrange the blocks again?

Solution:

Here, we will have to find the factor pairs of total number of blocks present with Annabelle.

i.e. 42

First of all, let us have a look at the factor pairs of 42.

Therefore, the other two factor pairs can be 2, 21 and 1, 42.

The other two possible factor pairs are:

21 rows 2 blocks

1 row 42 blocks

pls help me I need this last question ⁉️
[tex]46 + \frac{3}{7} \times = [/tex]

Answers

Answer:

[tex] \sf 46 \frac{3}{7} [/tex]

Step-by-step explanation:

[tex] \sf = 46 + \frac{3}{7} [/tex]

[tex] \sf = 46 \frac{3}{7} [/tex]

or

[tex] \sf = 46 + \frac{3}{7} [/tex]

[tex] \sf = \frac{46}{1} + \frac{3}{7} [/tex]

[tex] \sf = \frac{322}{7} + \frac{3}{7} [/tex]

[tex] \sf = \frac{325}{7} [/tex]

[tex] \sf = 46 \frac{3}{7} [/tex]

Answer:

325/7

Step-by-step explanation:

refer to the attachment

hope it helps

whats 50 times 100 the answer

Answers

Answer: 50 * 100 = 5000

Step-by-step explanation:

a simple way of multiplying numbers that are a 1 with zeros is by simply moving the zeros from that number to the other number

100 has 2 zeros, so you ad them to the 50. 50 with 00 is 5000

Answer: 5O x IOO = 5OOO

Step-by-step explanation:

5OOO, think of it like 5 x 1, 5 x 1 = 5, now add 3 zero’s since there are 3 zeros.

Help me please people it’s the last question

Answers

Answer:

1 m³

Step-by-step explanation:

first find volume of smaller cubes

V = lwh

S = 1/3*1/3*1/3

S = 1/27

find volume of large cube. there are 27 smaller cubes.

V = 27S

V = 27(1/27)

V = 1

S: volume of small cube

V: volume of large cube

I did it on the page so that you understand

You rent an apartment that costs \$800$800 per month during the first year, but the rent is set to go up 9.5% per year. What would be the rent of the apartment during the 9th year of living in the apartment? Round to the nearest tenth (if necessary).\
Pls help I'm dying here

Answers

Answer:

Monthly rent for Year 9: $1,653.5

Total cost of rent for the whole 9th year: $19,841.9

Step-by-step explanation:

Given the monthly rent of $800 for an aparment, for which it is set to increase by 9.5% annually:

Increase in the Monthly Cost of RentYear 1:

The monthly rent will stay at $800 for the first year.  

Year 2:

For year 2, we must add the 9.5% increase in the monthly rent. In order to determine the 9.5%, simply multiply the monthly rent by 0.095 (the decimal equivalent of 9.5%), then add the product to the monthly rent in year 1 of $800.

9.5% increase for Year 2:  $800 × 0.095 = $76

Monthly rent in Year 2:  $800 + $76 = $876

Year 3:

For year 3, we must add the 9.5% increase in the monthly rent from Year 2 ($876).  

9.5% increase for Year 3:  $876 × 0.095 = $83.22

Monthly rent in Year 3:  $876 +  $83.22 = $959.22

Year 4:

For year 4, we must add the 9.5% increase in the monthly rent from Year 3 ($959.22).  

9.5% increase for Year 4:  $959.22 × 0.095 = $91.13

Monthly rent in Year 4: $959.22 +   $91.13 = $1,050.35

Year 5:

For year 4, we must add the 9.5% increase in the monthly rent from Year 4 ($1,050.35).  

9.5% increase for Year 5:  $1,050.35 × 0.095 = $99.78

Monthly rent in Year 5: $1,050.35 + $99.78 = $1,150.13

Year 6:

9.5% increase for Year 6:  $1,150.13 × 0.095 = $109.26

Monthly rent in Year 6:  $1,150.13 + $109.26 = $1,259.39

Year 7:

9.5% increase for Year 7:  $1,259.39 × 0.095 = $119.64

Monthly rent in Year 7:  $1,259.39 + $119.64 = $1,379.03

Year 8:

9.5% increase for Year 8:  $1,379.03  × 0.095 = $131.00

Monthly rent in Year 8:  $1,379.03 + $131.00 = $1,510.04

Year 9:

9.5% increase for Year 9:  $1,510.04  × 0.095 = $143.45

Monthly rent in Year 9:  $1,510.04 + $143.45 = $1,653.50

Yearly Cost of Rent:

In order to determine the yearly cost of renting an apartment, simply multiply  monthly rent by 12. In other words:

Year 1: $800 × 12 = $9600

Year 2: $876 × 12 = $10,512

Year 3: $959.22 × 12 = $11,510.64

Year 4: $1,050.35 × 12 = $12,604.15

Year 5: $1,150.13 × 12 = $13,801.55

Year 6: $1,259.39 × 12 = $15,112.69

Year 7: $1,379.03 × 12 = $16,548.40

Year 8: $1,510.04 × 12 = $18,120.50

Year 9: $1,653.50 × 12 = $19,841.94

Therefore, due to the 9.5% annual increase in rent, the monthly cost of an apartment during the 9th year is $1,653.5, or $19,841.9 (12-months' worth of rent).

❗❗ANSWER+EXPLANATION=100POINTS+BRAINLIEST♡❗❗

(Question in the pic)

thanks <3​

Answers

Answer:

Generally, the algebraic expression should be any one of the forms such as addition, subtraction, multiplication and division. To find the value of x, bring the variable to the left side and bring all the remaining values to the right side. Simplify the values to find the result.

Step-by-step explanation:

write a subtraction sentence where the difference is negative use a positive and negative integer ​

Answers

Answer:

Examples:

-5 - 2

-4 - 1

-8 - 6

Basically, the negative integer should be first with the higher greater absolute value.

Step-by-step explanation:

Answer:

-7-(-6)

Step-by-step explanation:

=-1.

it contains a positive and negative integer

Hiya! I need help i bet it says im in high school but im in middle school can you tell me what percent of 25 is 20 in middle school

Answers

Answer:

25 percent of 20 is 5 percent

Answer:

Step-by-step explanation:

percentage:

80%

messed up saying it was 125% so say thanks to the person who commented below mine-

Put the following equation of a line into slope-intercept form, simplifying all fractions.
2
x
+
6
y
=
2x+6y=


12
12

Answers

Answer:

[tex] \sqrt[6]{ 729} [/tex]

If one team had 7 players, how many players did the other team have

Answers

7 I think don’t quote me on it

Answer:7

Step-by-step explanation:because each team has to be equal

On a sunny day Josée's shadow
is 2.9 m long, while the shadow
of a tower is 11.3 m long. If
Josée is 1.8 m tall, calculate
the height of the tower.

Answers

Answer:

sorry I don't know the answer to this question

Please help!!!!!!!!!!!!!!!

Answers

Answer:

Y+5=2/3(x-4)

Step-by-step explanation:

since the slope is 2/3, it should be in the right side of the equal sign, its passing thru (4,-5) thus it being Y+5=2/3(x-4)

3 t-shirts cost £25.95.
How much do 10 t-shirts cost?

Answers

Answer:

£86.50

Step-by-step explanation:

To find how much 10 t-shirts cost we have to find how much they cost individually.

3 T- Shirts / 25.95 = 8.65 which means that each T-Shirt Costs 8.65.

8.65 x 10 T-Shirts = £86.50

HELP!!!!!!!!!!!!!!!!!

Answers

Answer:

Not possible

Step-by-step explanation:

R : 2 row x 3 column

P: 2 row x 2 column

column of first matrix (R) is not equal to the row of 2nd matrix

R*P : not possible

find an equation of the line parallel to y=2x+3 and that passes through the point (5,3)

Answers

Answer:

y = 2x - 7

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

y = 2x + 3 ← is in slope- intercept form

with slope m = 2

Parallel lines have equal slopes , then

y = 2x + c ← is the partial equation

To find c substitute (5, 3 ) into the partial equation

3 = 10 + c ⇒ c = 3 - 10 = - 7

y = 2x - 7 ← equation of parallel line

Answer:

y = 2x - 7

Step-by-step explanation:

First line: y = 2x + 3 , m = 2

Second line: m = 2 and pass ( 5 , 3 )

y - 3 = 2( x - 5 ) ⇔ y = 2x - 7

Find the base of
4+6 = 20​

Answers

Answer:

So in base 5, 4+6 = 20

Step-by-step explanation:

the length of a rectangle is 5 less than 2 times its width, if the perimeter is 86ft, what is the length and width of the rectangle. Write and solve the equation

Answers

Answer:

Width: 16

Length: 27

Step-by-step explanation:

Let x be the width of the rectangle.

The length would then be 2x - 5

The perimeter is:

2x - 5 + x + 2x - 5 + x =

6x - 10 = 86

Solve.

6x = 96

x = 16

Thus,

Width: 16

Length: 27

The website is Investor.gov’s compound interest calculator.

I need help answering.

Answers

Answer:

its a website or

Step-by-step explanation:

PLEASE HELP! I WILL GIVE BRAINLIEST <3

A regulation football field is 300 feet by 160
feet, with 30 foot end zones at either end of
the longer side. What is the distance from the
back corner of one end zone to the opposite
front corner of the other, as denoted by the
dashed line in the picture to the left?

Answers

Answer:

10 <3

Step-by-step explanation:

Answer:

340ft

Step-by-step explanation:

So this is just the Pythagoren Theorem. a^2+b^2=c^2

340ft

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