In 2012, the world population was 7.02 billion. The birth rate had stabilized to 134 million per year and is projected to remain constant. The death rate is projected to increase from 56 million per year in 2012 to 80 million per year in 2040 and to continue increasing at the same rate.
(a) Assuming the death rate increases linearly, write a differential equation for P(t), the world population in billions t years from 2012.
(b) Solve the differential equation.
(c) Find the population predicted for 2050.
Answer:
[tex](a)\ \frac{dP}{dt} = 0.078- 0.000857t[/tex]
[tex](b)\ P = 0.078t- 0.0004285t^2 + 7.02[/tex]
[tex](c)\ 9.37\ billion[/tex]
Step-by-step explanation:
Given
In 2012
[tex]P(t) = 7.02\ billion[/tex]
[tex]R_1 = 134\ million/year[/tex] --- Birth rate
[tex]R_2 = 56\ to\ 80[/tex] -- Death rate from '12 to '40
Solving (a): Equation for population from 2012
In 2012, we have the addition in population to be:
[tex]\triangle P= Birth - Death[/tex]
[tex]\triangle P= 134 - 56[/tex]
[tex]\triangle P = 78[/tex] million
From 2012 to 2040, we have the death rate per year to be:
[tex]Rate/yr = \frac{80 - 56}{2040 - 2012}[/tex]
[tex]Rate/yr = \frac{24}{28}[/tex]
[tex]Rate/yr = \frac{6}{7}[/tex] million/year
So, the differential equation is:
[tex]\frac{dP}{dt} = \triangle P - Rate/yr * t[/tex] where t represents time
[tex]\frac{dP}{dt} = 78 - \frac{6}{7} * t[/tex]
[tex]\frac{dP}{dt} = 78 - \frac{6t}{7}[/tex]
Express in millions
[tex]\frac{dP}{dt} = \frac{78}{1000} - \frac{6t}{7000}[/tex]
[tex]\frac{dP}{dt} = 0.078- 0.000857t[/tex]
Solving (b): The solution to the equation in (a)
[tex]\frac{dP}{dt} = 0.078- 0.000857t[/tex]
Make dP the subject
[tex]dP = (0.078- 0.000857t)dt[/tex]
Integrate both sides
[tex]\int dP = \int (0.078- 0.000857t)dt[/tex]
[tex]P = \int (0.078- 0.000857t)dt[/tex]
This gives:
[tex]P = 0.078t- \frac{0.000857t^2}{2} + c[/tex]
[tex]P = 0.078t- 0.0004285t^2 + c[/tex]
Solve for c.
When t = 0; P = 7.02
So, we have:
[tex]7.02 = 0.078*0- 0.0004285*0^2 + c[/tex]
[tex]7.02 =0-0 + c[/tex]
[tex]7.02 =c[/tex]
[tex]c = 7.02[/tex]
So:
[tex]P = 0.078t- 0.0004285t^2 + c[/tex]
[tex]P = 0.078t- 0.0004285t^2 + 7.02[/tex]
Solving (c): The population in 2050
We have:
[tex]P = 0.078t- 0.0004285t^2 + 7.02[/tex]
In 2050, the value of t is:
[tex]t = 2050 - 2012[/tex]
[tex]t = 38[/tex]
So, the expression becomes
[tex]P = 0.078*38- 0.0004285*38^2 + 7.02[/tex]
[tex]P \approx 9.37\ billion[/tex]
Lesson 18: Exponentials Unit Test Algebra 1 B Unit 5: Exponentials
What is the value of the function? f(x)=(−2)3(3)0(4)−2
−3/2
0
−3/4
−1/2
Simplify the expression (45y5y744y9)2
This is a 17 question test those are the first 2 please try and find all 17 you have the title first to give all 17 will get brainlist
Answer:
search mo po sa goggle
Answer:
id k the first one
Simplify the expression (45y5y744y9)2 =
90[tex]y^{758}[/tex]
Isaac's finish 7 heavy cleans every 5 minutes Ryan finish heavy 8 clean every 4 minutes how many more cleans did Isaac complete than
Ryan
Answer:
12 more cleans
Step-by-step explanation:
You need to make each person have done work the same amount of time that is a multiple of 4 and 5. The closest is 20. So multiply 5 to 8 cleans for Ryan and 4 to 7 cleans for Issac. 40 cleans for Ryan - 28 cleans for Issac = 12 more cleans for RYAN, not Issac.
Ceasar opens a bank account and makes an initial deposit of $800. The banker tells Ceasar that he is going to receive an annual rate of 10% compounded continuously on his investment. Find the bank balance assuming Ceasar leaves the account untouched for 8 years.
Can you please do the problem using the formula A(t)=pe^(rt).
Answer:
1780.43
Step-by-step explanation:
Given:
P = 800
r = 10% or 0.1
t = 8
Work:
[tex]A=Pe^{rt}\\\\A=800e^{0.1*8}\\\\A=800e^{0.8}\\\\A=1780.43[/tex]
Two hockey teams, the Winnipeg Jets (yay!) and the Toronto Maple Leafs (boo!), miraculously make it to
the Stanley Cup finals. As soon as a team wins 3 games, the championship is over.
The schedule for the playoffs (for home games) is: Jets - Leafs - Jets - Leafs - Jets
If the Jets are playing at home, there is a 60% chance they'll win. If they are playing on the road, there is
a 45% chance they'll win.
Find the probability that the Jets win the Stanley Cup. Round answers to at least 4 decimal places.
Can anyone help me please. No links please
Answer: 58 .23
Step-by-step explanation:
Jets are playing at home, there is a 60% chance they'll win. If they are playing on the road, there is
a 45% chance they'll win.
help me please i’ll give you brainliest
Answer:
He should have canceled x
Are these ratios equivalent?
28 hot dogs to 50 hamburgers
15 hot dogs to 30 hamburgers
Answer:
Step-by-step explanation:
28 : 50 and 15 : 30
14 : 25 and 1 : 2 are not equivalent
Jason jumped off a cliff into the ocean in Acapulco while vacationing with some friends. His height as a function of time could be modeled by the function h(t) = -16t^2 +16t+480
How long did it take Jason to reach his maximum height?
Answer:
5 seconds
Step-by-step explanation:
I did the same question a while ago.
Please help I will give brainlist thanks
Answer:
still need help?
Step-by-step explanation:
2 1/4 yd x 1/4 yd
stuck, please help
Answer:
9/16 yd^2
Step-by-step explanation:
2 1/4 as an improper fraction is 9/4, 9/4 * 1/4 = 9/16, and since you are multiplying two yards, thats yard^2, so 9/16 yd^2
20% of _____ is 18
what is the blank
Answer:
90
Step-by-step explanation:
Help a brother out pls
I have a f because of this assignment pls help
Answer:
error: "I was a newly caged animal that rushed about"
correction: "I was like a newly caged animal that rushed about"
an influencer had 400 subscribers in January. The number of subscribers have grown by a factor of 1.5 every month since then. write a sequence that represents the number of subscribers for the three months that followed (january through april)
Answer:
y=400(1.5)^4
Step-by-step explanation:
My question... please answer asap
Answer:
slope=1/4
y-intercept=3
y=.25x+3
Step-by-step explanation:
slope=rise over run so
slope=1/4
y-intercept is the value of y where the line crosses the y axis..
y-intercept=3
In y=mx+b form m is slope and b is y-intercept so...
y=.25x+3
AB is the mindset of the trapezoid. Find the value of X.
Answer:
AB has a bad mindset :(
X is valued a lot bc he helps out AB
the graph shows the height y, in feet, of a balloon that is launched from a platform 13.5 feet high, as a quadratic function of x, the time in seconds. What is the domain of this function in this situation?
Answer:
B) 0<=x<=54
Step-by-step explanation:
The domain of the function is,
0 ≤ x ≤ 54.
What is domain?The collection of all conceivable independent values that a function or relation may take is known as its domain.
Given:
The graph is given in the attached image.
The graph shows the height y, in feet, of a balloon that is launched from a platform 13.5 feet high, as a quadratic function of x, the time in seconds.
The domain of the function is those value where the function is defined.
The domain of the function is,
0 ≤ x ≤ 54.
Therefore, 0 ≤ x ≤ 54 is the domain.
To learn more about the domain;
https://brainly.com/question/28135761
#SPJ2
A toy manufacturer wants to know how many new toys children buy each year. A sample of 305 children was taken to study their purchasing habits. Construct the 80% confidence interval for the mean number of toys purchased each year if the sample mean was found to be 7.6. Assume that the population standard deviation is 1.5. Round your answers to one decimal place.
Answer:
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1 - 0.8}{2} = 0.1[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1 - \alpha[/tex].
That is z with a pvalue of [tex]1 - 0.1 = 0.9[/tex], so Z = 1.28.
Now, find the margin of error M as such
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
[tex]M = 1.28\frac{1.5}{\sqrt{305}} = 0.1[/tex]
The lower end of the interval is the sample mean subtracted by M. So it is 7.6 - 0.1 = 7.5
The upper end of the interval is the sample mean added to M. So it is 7.6 + 0.1 = 7.7
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.
A computer generates a two-digit number random number. It can be any number from 00 to 99.
Find the probability that it is 99
Answer:
1/99
Step-by-step explanation:
total is 99 and there is only one 99 between 0-99 so the probability is 1/99
Luis solved the following equation below: - x ^ 2 + 10x - 21 = y Line Line Line 1x = (- (10) plus/minus sqrt((10) ^ 2 - 4(- 1) * (- 21)))/(2(- 1)) 2x = (- 10 plus/minus sqrt(100 - 84))/- 2 3x = (- 10 plus/minus sqrt(16))/- 2 Line 4 x= -10 pm sqrt 4 -2 5x = (- 10 plus/minus 2)/- 2 Linedx = (- 10 + 2)/- 2 x = (- 10 - 2)/- 2 x = - 8/- 2 x = - 12/- 2 Line Line 7 Line 8 x = 4 x = 6 Did Luis solve the above function properly ? Justify why or why not and be specific (use the line numbers as reference
Answer:
Sorry try using the math tool.... it looks like a square root sign with a x inside of it! :)
[tex]\sqrt{x}[/tex] <-- pretty much like this one and is at the bottom of your brainly tab :)
It makes things clearer when it comes to these sort of things and eliminates things like, " plus/minus, sqrt, Linedx, 2 Line Line 7 Line 8x = 4x =6
Hope this helps :)
Step-by-step explanation:
Answer:
x = 7, x = 3Steps:
-x²+10x-21 = 0
x = (-10±√(10²-4×(-1)×(-21)))/2×(-1)
x = (-10±√(100-84))/-2
x = (-10±√16)/-2
x = (-10±4)/-2
x = (-10-4)/-2 , x = (-10+4)/-2
x = -14/-2 , x = -6/-2
x = 7 , x = 3
Luis did not solve the equation properly!
HELP PLEASE! I WILL GIVE BRAINLIEST
Answer:
13.89
Step-by-step explanation:
A^2+B^2=C^2
7^2+12^2=C^2
193 = C^2
193 square root = 13.89
Complete the sentence.
9 is 36% of
Answer:
3.24
Step-by-step explanation:
9 takes up 3.24 of 36%
Answer:
9 is 36% of 25
Step-by-step explanation:
36%×x=9
36/100×x=9
x=9×100/36
x=25
Trigonometric ratios can be used with any type of triangle.
O
True
O
False
Answer:
True
Step-by-step explanation:
Answer:
True
Step-by-step explanation:
I don’t get this I need help if you get it right I will mark you as brainlest
Answer:
Step-by-step explanation:
A nurse administers 25 milligrams of a drug to a patient. The amount of the drug, A, in milligrams, left in the patient after thours can be modeled by the function A(t) = 25e 0.354
How many hours will it take for the amount of the drug left in the patient to drop to 0.25 milligrams? Round your answer to the nearest tenth of an hour.
hours
Pls helppp
Answer:
heyy guyss how r u all I'm Aditya from. India I've changed my server to Ireland is this Ireland
Step-by-step explanation:
and plss guyss fo llo w me
56. The zip code of a location consists of five digits chosen from the set Z shown below.
Z= {0, 1, 2, 3, 4, 5, 6, 7, 8,9}
The set L represents the digits in the zip code for Key Largo.
L = {3,3,0,3,7)
The set K represents the digits in the zip code for Killarney.
K= {3,4,7,4,0}
How many odd numbers are in the set "(L UK)?
Answer:
2 I.e 3 and 7
Step-by-step explanation:
(L U K)={0,3,4,7} [ elements are not repeated in set ]
odd numbers = 3 & 7
Ceasar opens a bank account and makes an initial deposit of $800. The banker tells Ceasar that he is going to receive an annual rate of 10% compounded continuously on his investment. Find the bank balance assuming Ceasar leaves the account untouched for 8 years.
Can you please do the problem using the formula A(t)=pe^(rt).
WALLAHI HELP ME PLEASE
9514 1404 393
Answer:
(a) yes
Step-by-step explanation:
Put the numbers in for x and y and see if you get a true statement.
5 ≤ 2(4) +1
5 ≤ 9 . . . . . . true
The point is a solution.
Please help I need it soon
Answer:
[tex](3 \times 12) + (3 \times 3 \times 0.5)[/tex]
Step-by-step explanation:
answer is 40.5 . please like my answer and brainliest me HSHSSHSHS
Ava read 126 books in 12 months. How many books per month did she read? Show your work
2. Rosa made a mosaic wall mural using 15 black tiles, 60 blue tiles, and 25 red tiles. Write a percent to represent the number of red tiles that were used in the mural.
9514 1404 393
Answer:
25%
Step-by-step explanation:
The ratio of red tiles to all tiles is ...
25/(15 +60 +25) = 25/100 = 25%
25% of the tiles were red tiles.
_____
Additional comment
It is often useful to think of the % symbol as being equivalent to /100, and vice versa.