(a) Find the average rate of change of the area of a circle with respect to its radius r as r changes from 2 to each of the following.
(i) 2 to 3
(ii) 2 to 2.5
(iii) 2 to 2.1
(b) Find the instantaneous rate of change when r =2.

Answers

Answer 1

Answer:

ai) 5pi

aii) 4.5pi

aiii) 4.1pi

b) 4pi

Step-by-step explanation:

a) Area of a circle is given by pi×r^2.

The average rate of change of the area of a circle from r=b to r=a is (pi×b^2-pi×a^2)/(b-a).

Let's simplify this.

Factor pi from the terms in the numerator:

pi(b^2-a^2)/(b-a)

Factor the difference of squares in the numerator:

pi(b-a)(b+a)/(b-a)

"Cancel" common factor (b-a):

pi(b+a).

So let's write a conclusive statement about what we just came up with:

The average rate of change of the area of a circle from r=b to r=a is pi(b+a).

i) from 2 to 3 the average rate of change is pi(2+3)=5pi.

ii) from 2 to 2.5 the average rate of change is pi(2+2.5)=4.5pi.

from 2 to 2.1 the average rate of change is pi(2+2.1)=4.1pi.

b) It looks like a good guess at the instantaneous rate of change is 4pi following what the average rate of change of the area approached in parts i) through iii) as we got closer to making the other number 2.

Let's confirm by differentiating and then plugging in 2 for r.

A=pi×r^2

A'=pi×2r

At r=2, we have A'=pi×2(2)=4pi. It has been confirmed.


Related Questions

The length of a rectangle is 3 ft longer than its width.
If the perimeter of the rectangle is 42 ft, find its area.

Answers

Answer:

A = 108 feet²

Step-by-step explanation:

Let the width is b.

Length = 3+b

Perimeter of the rectangle, P = 42 ft

Perimeter = 2(l+b)

42 = 2 (3+b+b)

21 = (3+2b)

21-3 = 2b

18 = 2b

b = 9 feet

Length, l = 3+9 = 12 feet

Area of the rectangle,

A = lb

So,

A = 12 × 9

A = 108 feet²

So, the area of the rectangle is 108 feet².

five brothers of 4, 9, 11, 13 and 16 years respectively, receive an inheritance of 1,500,000, the will stipulated that that amount must be shared by the heirs so that, placed the shares in a bank, they would result in equal capitalized amounts, when each one reached 21, could raise his share. Knowing that the bank charges an interest rate of 9% per year, what is the amount of each share?

Answers

9514 1404 393

Answer:

Youngest to oldest:

160,406.86246,805.83293,230.01348,386.58451,170.72

Step-by-step explanation:

At 9% interest per year, the present value of 1 at age 20 is ...

  p(a) = 1.09^(a-20)

Adding the present values for the different ages, we get a total of about 2.35528984846. Dividing the inheritance by that amount gives the multiplier for each of the present value numbers. The result is the list of shares shown above. At age 20, each brother will inherit about 636,864.29.

__

Additional comment

This is the sort of question that suggests the use of a graphing calculator or spreadsheet for doing the tedious number crunching.

(We assume the bank pays 9% per year, rather than charges 9% per year.)

Si una mujer gana más que su marido

Answers

Answer:

nada está bien gana bien.

Find the local linear approximation L(x) of the function f(x) = 5−x^2 at x = 2.
Use this to estimate f(2.1).

Answers

Answer:

L(x)=-4x+9

L(2.1)=0.6

Step-by-step explanation:

It's asking us to find the tangent line to curve f(x) = 5−x^2 at x = 2.

Theb use this to estimate f(2.1).

To find slope of tangent line, we must differentiate and then plug in 2 for x.

f'(x)=0-2x by constant and power rule.

f'(x)=-2x

So the slope of the tangent line is -2(2)=-4.

A point on this tangent line shared by the curve is at x=2. We can find it's corresponding y-value using f(x)=5-x^2.

f(2)=5-(2)^2

f(2)=5-4

f(2)=1

So let's rephrase the question a little.

What's the equation for a line with slope -4 and goes through point (2,1).

Point-slope form y-y1=m(x-x1) where m is slope and (x1,y1) is a point on the line.

Plug in our information: y-1=-4(x-2).

Distribute: y-1=-4x+8

Add 1 on both sides: y=-4x+9

Let's call this equation L(x), an expression to approximate value for f near x=2.

L(x)=-4x+9

Now the appropriation at x=2.1:

L(2.1)=-4(2.1)+9

L(2.1)=-8.4+9

L(2.1)=0.6

If we did plug in 2.1 into given function we get 5-(2.1)^2=0.59 . This is pretty close to our approximation above.

The entrance ticket for a carnival costs $89.97, which includes a royal meal
that costs $10.85, 1 play station game, and 3 water rides (Each water ride
costs the same price). The cost of a water ride is twice as that of a play
station game. Find the cost of a water ride. Estimate to the nearest tenths.

Answers

Subtract the meal:

89.97- 10.85 = 79.12

Let the play station game = x

A water ride is twice that so a water ride is 2x

There is 3 water rides : 3 x 2x =6x

The PlayStation game and water rides = 79.12

6x + x = 79.12

Simplify:

7x = 79.12

Divide both sides by 7:

X = 11.30

The PlayStation game is 11.30

The water ride = 2 x 11.30 = 22.60

Help me plz will mark brainliest

Answers

Step-by-step explanation:

Given,

the bigger triangle (∆GFH), <HGF = 90° and <GFH = 60° and GF = 4

In the 30-60-90 triangle, FH = 4×2 = 8

or you can find it like this,

cos60 = 4/FH

FH = 4/cos60 = 8

Now, I is the midpoint of FH, so, FI = 8/2 = 4

now for ∆FGI,

<GFI = 60°, GF = 4, FI = 4, it's a equilateral triangle, so we can say GI = 4

Now we need to find the height of ∆FGI, for that,

area of ∆FGI = (√3/4)×4² = 4√3 = 6.92820323..

So height (GJ) = 2×area/side = 2×4√3/4 = 2√3 = 3.46410162.. [height of ∆GFI (Because altitude is perpendicular distance from a point) = GJ, given]

now, in ∆GJI, GJ = 2√3, GI = 4 and <GJI = 90° (since itsy altitude, the angle will be a right angle, i.e. 90°)

So, JI = √{4²-(2√3)²} = 2

Area = 2×2√3/2 = 2√3 = 3.46410162.. = 3.46 (rounded to the nearest hundredth)

The table below shows some inputs and outputs of the invertible function f with domain all real numbers.

Answers

Answer:

f^-1 (-15) = -6

f^-1(4) + f(9)  = 0

Step-by-step explanation:

f^-1 (-15) =

Look where the output is -15 and  find the x value ( x=-6)

Since where are using the inverse function, the input becomes the output and  the output  and the output becomes the input

f^-1 (-15) = -6

f^-1 (4) = -11  (inverse function)

f(9) = 11  ( regular function)

f^-1(4) + f(9) = -11+11 = 0

Consider the line y = 4x + 9. If a second line is perpendicular to this one, what is its slope?

Answers

Answer:

Step-by-step explanation:

slope of line perpendicular to y=mx+c is -1/m

so here reqd. slope=-1/4

Find x. Round your answer to the nearest tenth of a degree.

Answers

Answer:

x = 55.8

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

cos theta = adj / hypotenuse

cos x = 9/16

Taking the inverse cos of each side

cos^-1 (cos x) = cos^-1 (9/16)

x=55.77113

To the nearest tenth

x = 55.8

Answer:

Relative to x, the side of 16 is the hypotenuse, and the side of 9 is adjacent.

So we think, what trigonometric property relates hypotenuse and adjacent sides of a right triangle?

SOH CAH TOA

We can use the COSINE function to solve in this case, as we have both  the ADJACENT SIDE (A) and the HYPOTENUSE (H).

Cosine = Adjacent/Hypotenuse

Cosine (x) = 9/16

Angle x = 55.8 degrees.

Let me know if this helps!


Carter buys a one-gallon bottle of juice for $23.04. What is the unit rate of the cost of the juice per fluid ounce?
1 gallon
=
1 gallon=


4 quarts
4 quarts
1 quart
=
1 quart=


2 pints
2 pints
1 pint
=
1 pint=


2 cups
2 cups
1 cup
=
1 cup=


8 fluid ounces
8 fluid ounces
Before you try that problem, answer the question below.
How many fluid ounces of juice did Carter buy?

Answers

1 gallon = 4 quarts

4 quarts = 8 pints

8 pints = 16 cups

16 cups = 128 fluid ounces

He bought 128 ounces

Select the correct answers in the table.
Rachel enjoys exercising outdoors. Today she walked 5 2/3 miles in 2 2/3 hours. What is Rachel’s unit walking rate in miles per hour and in hours per mile?

Answers

Rachel enjoys exercising outdoors. Today she walked 5 2/3 miles in 2 2/3 hours. What is Rachel's unit walking rate in miles per hour and in hours per miles? 5 2/3 / 2 2/3 = 17/3 / 8/3 = 17/3 x 3/8 = 17/8 = 2 1/8 miles per hour.

The 25th percentile for waiting time in a doctor's office is 25 minutes. The 75th percentile is 40 minutes. The interquartile range (IQR) is

Group of answer choices

15 minutes.

14 minutes.

impossible to determine without knowing n.

13 minutes.

Answers

Answer:

15 minutes

Step-by-step explanation:

The IQR is the range between Q1 and Q3. The quartile that represents 25% is Q1 and 75% is Q3. So, to solve find the range between 75% and 25%. The range is the difference. Therefore, subtract 25 from 40 to get the final answer, 15 minutes.

Give example to verify if the given statement is true or false
1) if two numbers are co-primes , at least one of them should be prime number.

Answers

Answer:

no

Step-by-step explanation:

if two numbers are co-prime that is not necessary that one of them must be a prime number

A popular beach erodes 4 inches per year on average.

An eroding beach.
A. How many years will it take for the coastline to erode one foot?

Answers

Answer:

3 years

Step-by-step explanation:

4 inches per year on average

1 foot = 12 inches

12 divided by 4 equals 3

therefore it is 3 years

accountancy

So i have to make trial balance and im kinda confused with 'interest'. So which side did it go to? Credit or debit? It didn't state the interest as received or expense/paid. someone told me to look at the bank but hey i need more explanation T^T​​

Answers

You would do credit because debit is not the one

Determine the quadrant in which the terminal side of the given angle lies. -750°

Answers

Answer:

Quadrant 4

Step-by-step explanation:

If the given angle was positive, then we go clockwise.

But it's negative so we go counterclockwise.

An alternative way of graphing

Quadrant 1 is 0-90°

Quadrant 2 is 90-180°

Quadrant 3 is 180-270°

Quadrant 4 is 270-360°

Subtract the given angle by 360 until no longer possible

750 - 360 = 390     390 - 360 = 30

Remember that this was originally a negative angle

Instead of going clockwise to quadrant 1, we go counterclockwise to quadrant 4, ending up at 330°

Individual claim sizes may be modeled by a uniform distribution function on the interval [$1000, $5000]. Eighty claims are examined. Assume claims are independent.
What is the approximate probability that total claims will be between $250,000 and $300,000?
a) 17%
b) 34%
c) 50%
d) 84%
e) 97%

Answers

I guess it’s c I’m not sure though


(5, 4)
11-5-2)
16.nat's the slope-intercept form of the equation of the line graphed in this figure?
O A. y = 5/3x + 1
O B.y=-3x + 1
O C. y = 3x + 1
O D.y = -5/3X - 1

Answers

Answer:

The answer is B. y=3/5x+1

express the following in standard form
1) 5,94,00,00,00,000

2) 6892.25
Plz tell​

Answers

Answer:

first one is going to be

5.94x10¹¹

second one is going to be

6.89225x10³

A fruit company delivers its fruit in two types of boxes: large and small. A delivery of 7 large boxes and 9 small boxes has a total weight of 192
kilograms. A delivery of 5 large boxes and 3 small boxes has a total weight of 114 kilograms. How much does each type of box weigh?

Answers

Let L be the weight of a large box and S be the weight of a small box. So we can set up two equations:

2L + 3S = 83
4L + 8S = 197

Solve for L or S in one of the equations and substitute it into the other equation and find the other unknown.

2L = 83 - 3S
L = (83 - 3S)/2

4(83 - 3S)/2 + 8S = 197
166 - 6S + 8S = 197
2S = 31
S = 15.5 kg
L = (83 - 3(15.5))/2 = 18.25 kg

HELPP plz don't send a file whats the answer and explanation plz if you can

Answers

Answer:

5/0 is not a rational number

Step-by-step explanation:

you cant divide by 0

Factors and rewrite the expression 25x-15​

Answers

Answer:

5(5x-3)

Step-by-step explanation:

The common factor in this expression is 5 so divide 5 to all the values

25/5=5

-15/5= -3

Put these values into parenthesis and leave the 5 on the left side and out of the parenthesis

5(5x-3)

Answer:

5(5x - 3)

Step-by-step explanation:

The greatest common factor here is 5. Divide each term by 5 and simplify.

25x/5 = 5x

15/5 = 3

Therefore, the answer is 5(5x - 3).

Ms. Lowder has 2 children, one in first grade and one in fifth grade. Both children need paper for school. Paper costs $2.29 per pack. If the first grader needs 2 packs of paper and the fifth grader needs 6 packs of paper, how much money will Ms. Lowder spend on paper?

Answers

2packs +6 packs=8packs$2.29×8=$18.32

the answer is she spend $18.32

Find the x-intercepts of the l equation y=3x-6

Answers

Answer:

(2,0)

Step-by-step explanation:

the x intercept is when 'y' is equal to 0 :

0 = 3x - 6

6 = 3x

x = 2

Answer:

(2,0)

Step-by-step explanation:

y = 3x-6

The x intercept is found by setting y = 0 and solving for x

0 = 3x-6

Add 6 to each side

6 = 3x-6+6

6 =3x

Divide each side by 3

6/3 = 3x/3

2 =x

The x intercept is

(2,0)

Examining and Interpreting a Statistical Report
To help make his case to potential investors in his invention, Martin found a poll conducted by Gallup, a well-known research organization. Take some time to read the report, and then answer the questions to analyze the merits and limitations of this survey.

Part A
The poll report includes a table titled, “Americans Using Cash Now Versus Five Years Ago, by Age.” The age intervals are not equal. Why do you think the Gallup organization chose the age intervals of 23–34, 35–54, and 55+ to display these results?

Answers

The Gallup organization chose the age intervals of 23–34, 35–54, and 55+ to display these results due to they wanted to identify the habits about the use of cash in the different stages of a person's life, differentiated by ranges of unequal age.

Application of statistics in the collection of information.

Although the most common case when preparing a frequency table is to develop equal ranges that allow the behavior of the respondents to be identified every certain number of possible values.

Example:

0.1 - 10 10.1 - 20 20.1 - 30

On some occasions, irregular or uneven ranges are used that refer to a specific market stage or niche.

In part A of the exercise, you can clearly identify the three stages of adult life that could change your money-use habits:

23 - 34: Group that could be called "young adults", possibly made up of university students, and people who recently started their work stage. 35 - 54: Group of "middle-aged people", made up of people who have been working and managing their finances for a long time, even those who are even close to retirement. 55 or more: People of the "third age" or close to said category, made up of pre-pensioners and pensioners or people who are no longer active in employment.

As you can see, each of these groups present great differences that, from the point of view of a person interested in investing in their invention, a poll report like this is more attractive to select the niche of potential investors based on the work stage of said person.

By this reason, The Gallup organization chose the age intervals due to their money-habits, depending on the stage of his/her life.

If you want to see another example about poll reports, you can use the next link: https://brainly.com/question/15223266?referrer=searchResults

Which functions represent a vertical stretch of the parent function, f(x) = 1/x? Check all that apply.
g(x) = 3/x
g(x) = -2/x
g(x) = 1/4x
g(x) = 5/2x
g(x) = 1/2x

Answers

Answer:

[tex]g(x) = \frac{3}{x}[/tex]

[tex]g(x) =-\frac{2}{x}[/tex]

[tex]g(x) =\frac{5}{2x}[/tex]

Step-by-step explanation:

Given

[tex]f(x)=\frac{1}{x}[/tex]

Required

Which represents vertical stretch of f(x)

The transformation is represented as:

[tex]g(x) = a* f(x)[/tex]

Where:

[tex]|a| > 1[/tex]

So, the functions are:

[tex]g(x) = \frac{3}{x}[/tex] ---- [tex]|3| > 1[/tex]

[tex]g(x) =-\frac{2}{x}[/tex] --- [tex]|-2|>1[/tex]

[tex]g(x) =\frac{5}{2x}[/tex] --- [tex]|\frac{5}{2}| > 1[/tex]

Answer:

the other person is correct if you need them quick it is a b and d

Step-by-step explanation:

Dad is twice as old as Junior. Gramps is twice as old as Dad. The sum of the three ages is 140. How old is Gramps?​

Answers

Answer:

80

Step-by-step explanation:

We can start of with Junior's age. Then if dad is twice as old as Junior, then we add 2 parts and get 3 parts. Then Gramps is twice as old as Dad so we add 4 parts and get 7 parts. Now we divided 140 by 7. We get 20. This is Junior's age. By looking at that, we know Dad is 40, and Gramps is 80.

Gramps is 80 years old.

Hi! I'm happy to help!

We can say that Junior is x years old. This would mean that Dad is 2x years old, and Gramps is 4x years old. All together, their age is 7x. We can write an equation to solve.

7x=140

Divide both sides by 7 to find out x.

x=20

This means that Junior is 20 years old. Dad is double that, so he is 40 years old. And Gramps is double that so he is 80 years old.

To check our answer we can add all of them together.

20+40+80

140

This means that Gramps is 80 years old.

I hope this was helpful, keep learning! :D

After how many years, to the nearest whole year, will an investment of $100,000 compounded quarterly at 4% be worth
$213,022?
Provide your answer below:

Answers

9514 1404 393

Answer:

  19 years

Step-by-step explanation:

The compound interest formula tells you the future value of principal P invested at annual rate r compounded n times per year for t years is ...

  A = P(1 +r/n)^(nt)

Solving for t, we get ...

  t = log(A/P)/(n·log(1 +r/n))

Using the given values, we find t to be ...

  t = log(2.13022)/(4·log(1 +0.04/4)) ≈ 19.000

The investment will be worth $213,022 after 19 years.

The productivity of a country is given by f(x, y) = 600x^2/3 y^1/3, where x and y are the amount of labor and capital.
a) Compute the marginal productivities of labor and capital when x = 125 and y = 64.
b) Use part (a) to determine the approximate effect on productivity of increasing capital from 64 to 66 units, while keeping labor fixed at 125 units.
c) What would be the approximate effect of decreasing labor from 125 to 124 units while keeping capital fixed at 64 units?

Answers

The answer is 15 divided by watermelon equals 18 845 when the sun goes down the moon comes up just stars stay around the air comes up yeah who wants a cantaloupe and a knife they answer is 42

each week a train travels the same route 47 times about how many times does the train travel the route 43 weeks?
Answers
1,500 times
200 times
150 times
2,000 times

Answers

Answer:

Roughly 2,000 times

Step-by-step explanation:

47 x 43 = 2,021

                                                  Thank You

 

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