what is the purpose of proof in mathematics?

Answers

Answer 1

The mathematical proofs are useful to show that a mathematical statement is true. Generally a mathematical proof use other statements like theorems, or axioms. Also mathematical proofs are useful to know if the development of a theoretical process in other areas like physics is well done. Other thing that is useful of the proofs in mathematics is that it use a formal language  with symbols that minimize the ambiguity and make it universal.


Related Questions

Which of the following equations have exactly one solution?
Choose all answers that apply:

Answers

Answer:

A and B

Step-by-step explanation:

It has exactly one solution if the slope is different on both sides. A and B has different slopes on both sides. There will only be one intersection thus only one solution.

If the slope is same on both sides then it either has infinite solutions if the equation can be reduced to true equation (e.g. 1 = 1). Or no solution if it can be reduced to false equation (e.g. 1 = 0)

2x + 9 = 83
HELP gOOD ANSWERS ONLY

Answers

Answer:

x = 37

Step-by-step explanation:

2x + 9 = 83

-9          -9

2x = 74

---    ----

2     2

x = 37

Hey!

----------------------------------------------------

Solution:

2x + 9 = 83

~Subtract 9 to both sides

2x + 9 - 9 = 83 - 9

~Simplify

2x = 74

~Divide 2 to both sides

2x/2 = 74

~Simplify

x = 37

----------------------------------------------------

Answer:

x = 37

----------------------------------------------------

Hope This Helped! Good Luck!

at the beginning of the day the stock market goes up 301/2 points. at the end of the day the stock market goes down 120 1/4 points. what is the total change in the stock market from the beginning of the day to the end of the day?

Answers

Answer:

just saying

Step-by-step explanation:

subtract them lol use a mixed number calculator online

let's change the mixed fractions first to improper fractions and then get their sum.

we don't know the beginning point of the market, however from that point on, it spikes up by 30½and then goes down by 120¼, we're being asked on the total change or namely the displacement, and that'd be the sum of the spike line going up and the dive line going down.

[tex]\bf \stackrel{mixed}{30\frac{1}{2}}\implies \cfrac{30\cdot 2+1}{2}\implies \stackrel{improper}{\cfrac{61}{2}}~\hfill \stackrel{mixed}{120\frac{1}{4}}\implies \cfrac{120\cdot 4+1}{4}\implies \stackrel{improper}{\cfrac{481}{4}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{481}{4}+\cfrac{61}{2}\implies \stackrel{\textit{using an LCD of 4}}{\cfrac{(1)481+(2)61}{4}}\implies \cfrac{481+122}{4}\implies \cfrac{603}{4}\implies 150\frac{3}{4}[/tex]

Need some assistance with the following problem.

Any equation or inequality with variables in it is a predicate in the domain of real numbers. For the following statement, tell whether the statement is true or false.

(3x)(x^2 − 4 = 1)

Answers

Answer:

The provided statement [tex]\exists x(x^2-4=1)[/tex] is true in the domain of real number.

Step-by-step explanation:

Consider the provided information.

Any equation or inequality with variables in it is a predicate in the domain of real numbers.

The provided statement is:

[tex]\exists x(x^2-4=1)[/tex]

Here, we need to find the value of x for which the above statement is true.

Since the value of x can be any real number so we can select the value of x as √5

(√5)²-4=1

5-4=1

Which is true.

Thus, the provided statement [tex]\exists x(x^2-4=1)[/tex] is true.

Many states are carefully considering steps that would help them collect sales taxes on items purchased through the Internet. How many randomly selected sales transactions must be surveyed to determine the percentage that transpired over the​ Internet? Assume that we want to be 95​% confident that the sample percentage is within two percentage points of the true population percentage for all sales transactions.

Answers

Answer:

96

Step-by-step explanation:

Step 1

Divide your confidence interval by 2. In this case the confidence is 95% = 0.095, so 0.095/2 = 0.0475

Step 2

Use either a z-score table or a computer to find the closest z-score for 0.0475 and you will find this value is 1.96

Step 3

Divide the margin error by 2. In this case, the margin error is 2%. When dividing this figure by 2, we get 1% = 0.01

Step 4

Divide the number obtained in Step 2 by the number obtained in Step 3 and square it

1.96/0.01 = 196 and 196 squared is 38,416

Step 5

As we do not now a proportion of people that purchase on line, we must assume this value is 50% = 0.5. Square this number and you get 0.25

Step 6

Multiply the number obtained in Step 5  by the number obtained in Step 4, round it to the nearest integer and this is an appropriate size of the sample.

38,416*0.25 = 9,604

You bought an investment for $1000 and 5 years later sold that investment for $1700. Taking into account compounding, what was your average annual return during the investment? Round your answer to the nearest tenth of a percent and use decimals

Answers

Answer:

11.196%

Step-by-step explanation:

Given:

Buying cost of the investment or the principle amount = $1000

Time, n = 5 years

Selling cost of investment or amount received = $1700

Now,

the formula for compound interest is given as:

[tex]\textup{Amount}=\textup{Principle}(1+r)^n[/tex]

here, r is the rate of interest

on substituting the respective values, we get

[tex]\textup{1700}=\textup{1000}(1+r)^5[/tex]

or

(1 + r)⁵ = 1.7

or

1 + r = 1.11196

or

r = 0.11196

or

r = 0.11196 × 100% = 11.196%

A poll found that a particular group of people read an average of 12.8 books per year. The pollsters are​ 99% confident that the result from this poll is off by fewer than 3.93 books from the actual average x. Express this situation as an inequality involving absolute​ value, and solve the inequality for x to determine the interval in which the average is likely to fall.

Answers

Answer: [tex]|x-12.8|\leq3.93[/tex]

The interval in which the average is likely to fall : [tex]8.87\leq x\leq16.73[/tex]

Step-by-step explanation:

Given : A poll found that a particular group of people read an average of 12.8 books per year.

The pollsters are​ 99% confident that the result from this poll is off by fewer than 3.93 books from the actual average x.

The inequality to express this situation involving absolute​ value will be :-

[tex]|x-12.8|\leq3.93\\\\\Rightarrow\ -3.93\leq x-12.8\leq3.93 \\\\\text{Add 12.8 on both sides , we get}\\\\\Rightarrow\ -3.93+12.8\leq x\leq3.93+12.8\\\\\text{Simplify}\\\\\Rightarrow\ 8.87\leq x\leq16.73[/tex]

Hence, the interval in which the average is likely to fall : [tex]8.87\leq x\leq16.73[/tex]

Final answer:

The problem involves using confidence intervals and absolute value inequalities. The poll results suggest that the actual average number of books read by the group per year is between 8.87 books and 16.73 books, with a 99% confidence level.

Explanation:

In this problem, the pollsters are 99% confident which means that the actual average (x) of books read by the group is within 3.93 books of the given average (12.8 books). This situation can be expressed as an inequality involving absolute value as follows: |x - 12.8| < 3.93

To find the interval of values that x (the actual average) can take, we will solve the inequality for x. This inequality is saying that the distance between x (actual average) and 12.8 is less than 3.93.

This gives us two inequalities when broken down:  x - 12.8 < 3.93 and -(x - 12.8) < 3.93. Solving these two inequalities gives us an interval for x as 8.87 < x < 16.73.

So, the pollsters are 99% confident that the actual average number of books read by the group per year is between 8.87 books and 16.73 books.

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Given angle 1 has a measure of 3x + 6 and angle 2 has a measure of x, what is the measure in degrees of angle 1 if the two angles are supplementary?

Question 4 options:

136.5°


130.5°


43.5°

Answers

Answer:

Angle 1 = 3 . 43.5+6 =136.5°

Step-by-step explanation:

To angles are supplementary when added up, the result is 180°.

So:

Angle 1 + Angle 2 = 180°

We know that angle 1 = 3x+6 and angle 2= x

So we get:

[tex]3x+6+x=180\\4x+6=180\\4x=180-6\\4x=174\\x=174 : 4\\x=43.5[/tex]

If we know now that x=43.5, we can calculate the value of angle 1.

Angle 1 = 3 . 43.5+6 =136.5°

You manage an ice cream factory that makes two flavors: Creamy Vanilla and Continental Mocha. Into each quart of Creamy Vanilla go 2 eggs and 3 cups of cream. Into each quart of Continental Mocha go 1 egg and 3 cups of cream. You have in stock 700 eggs and 1350 cups of cream. How many quarts of each flavor should you make in order to use up all the eggs and cream? HINT [See Example 6.]

Answers

Answer:

You should make 250 quarts of Creamy Vanilla and 200 of Continental Mocha to use up all the eggs and cream.

Step-by-step explanation:

This problem can be solved by a first order equation

I am going to call x the number of quarts of Creamy Vanilla and y the number of quarts of Continental Mocha.

The problem states that each quart of Creamy Vanilla uses 2 eggs and each quart of Continental Mocha uses 1 egg. There are 700 eggs in stock, so:

2x + y = 700.

The problem also states that each quart of Creamy Vanilla uses 3 cups of cream and that each quart of Continental Mocha uses 3 cups of cream. There are 1350 cups of cream in stock, so:

3x + 3y = 1350

Now we have to solve the following system of equations

1) 2x + y = 700

2) 3x + 3y = 1350

I am going to write y as function of x in 1) and replace it in 2)

y = 700 - 2x

3x + 3(700 - 2x) = 1350

3x + 2100 - 6x = 1350

-3x = -750 *(-1)

3x = 750

x = 250

You should make 250 quarts of Creamy Vanilla

Now, replace it in 1)

y = 700 - 2x

y = 700 - 2(250)

y = 700 - 500

y = 200.

You should make 200 quarts of Continental Mocha

Final answer:

To use up all eggs and cream at the ice cream factory, the manager should produce 250 quarts of Creamy Vanilla and 200 quarts of Continental Mocha, by solving the system of linear equations derived from the given recipe requirements.

Explanation:

To solve the problem of how many quarts of Creamy Vanilla and Continental Mocha ice cream can be produced with 700 eggs and 1350 cups of cream, we need to set up a system of equations.

Let x be the number of quarts of Creamy Vanilla and y be the number of quarts of Continental Mocha.

From the information given:

2 eggs and 3 cups of cream are used for each quart of Creamy Vanilla.1 egg and 3 cups of cream are used for each quart of Continental Mocha.

We have the following equations:

2x + y = 700 (eggs)3x + 3y = 1350 (cups of cream)

To simplify the second equation we can divide by 3, resulting in:

x + y = 450

Now we solve this system of linear equations. By subtracting the second equation from the first, we get:

x = 700 - 450x = 250 quarts of Creamy Vanilla

Now, substitute x into the second equation:

250 + y = 450y = 450 - 250y = 200 quarts of Continental Mocha

To use up all the eggs and cream, the factory should make 250 quarts of Creamy Vanilla and 200 quarts of Continental Mocha.

Forty percent of world class tennis player are over 6 feet tall. 20 percent of the world class tennis players over 6 feet tall were premature babies. 30 percent of the world class tennis players who are not over 6 feet tall were premature babies. a. Calculate the probability that a randomly selected world class tennis player is over 6 feet tall and was a premature baby. Don't just write a number for the answer. Use the probability notation, simplify the answer, and show your work. b. Calculate the probability that a randomly selected world class tennis player is not over 6 feet tall and was not a premature baby. Don't just write a number for the answer. Use the probability notation, simplify the answer, and show your w ork.

Answers

Answer:

a) There is an 8% probability that a randomly selected world class tennis player is over 6 feet tall and was a premature baby.

b) There is a 42% probability that a randomly selected world class tennis player is not over 6 feet tall and was not a premature baby.

Step-by-step explanation:

In this problem, we have these following probabilities:

-A 40% probability that a world class tennis player is over 6 feet tall.

-A 60% probability that a world class tennis player is not over 6 feet tall.

-A 20% probability that a world class tennis player over 6 feet tall was a premature baby. This also means that there is a 80% probability that a world class tennis player over 6 feet tall was not a premature baby

-A 30% probability that a world class tennis player who is not over 6 feet tall was a premature baby. This also means that there is a 70% probability that a world class tennis player who is not over 6 feet tall was not a premature baby.

a. Calculate the probability that a randomly selected world class tennis player is over 6 feet tall and was a premature baby.

[tex]P = P_{1}*P_{2}[/tex]

[tex]P_{1}[/tex] is the probability that a random selected world class tennis player is over 6 feet tall. So

[tex]P_{1} = 0.4[/tex]

[tex]P_{2}[/tex] is the probability that a world class tennis player over 6 feet tall was a premature baby. So

[tex]P_{2} = 0.2[/tex]

[tex]P = P_{1}*P_{2} = 0.4*0.2 = 0.08[/tex]

There is an 8% probability that a randomly selected world class tennis player is over 6 feet tall and was a premature baby.

b. Calculate the probability that a randomly selected world class tennis player is not over 6 feet tall and was not a premature baby

[tex]P = P_{1}*P_{2}[/tex]

[tex]P_{1}[/tex] is the probability that a random selected world class tennis player is not over 6 feet tall. So

[tex]P_{1} = 0.6[/tex]

[tex]P_{2}[/tex] is the probability that a world class tennis player under 6 feet tall was not a premature baby. So

[tex]P_{2} = 0.7[/tex]

[tex]P = P_{1}*P_{2} = 0.6*0.7 = 0.42[/tex]

There is a 42% probability that a randomly selected world class tennis player is not over 6 feet tall and was not a premature baby.

Five students visiting the student health center for a free dental examination during National Dental Hygiene Month were asked how many months had passed since their last visit to a dentist. Their responses were as follows: 6 17 11 22 29 Assuming that these five students can be considered a random sample of all students participating in the free checkup program, construct a 95% confidence interval for the mean number of months elapsed since the last visit to a dentist for the population of students participating in the program.

Answers

Answer:

A 95% confidence interval for the mean number of months elapsed since the last visit to a dentist, is [tex][5.79063, 28.20937][/tex]

Step-by-step explanation:

We will build a 95% confidence interval for the mean number of months elapsed since the last visit to a dentist. A (1 - [tex] \alpha [/tex]) x100% confidence interval for the mean number of months elapsed since the last visit to a dentist with unknown variance and is given by:

[tex][\bar x -T_{(n-1,\frac{\alpha}{2})} \frac{S}{\sqrt{n}}, \bar x +T_{(n-1,\frac{\alpha}{2})} \frac{S}{\sqrt{n}}][/tex]

[tex]\bar X = 17[/tex]

[tex]n = 5[/tex]

[tex]\alpha = 0.05[/tex]

[tex]T_{(n-1,\frac{\alpha}{2})}=2.7764[/tex]

[tex]S = 9.0277[/tex]

[tex][17 -2.7764 \frac{9.0277}{\sqrt{5}}, 17 +2.77644 \frac{9.0277}{\sqrt{5}}][/tex]

A 95% confidence interval for the mean number of months elapsed since the last visit to a dentist, is    [tex][5.79063, 28.20937][/tex]

What is the area of the region bounded between the curves y=x and y=sqrt(x)?

Answers

Answer:

[tex]\frac{1}{6}[/tex]

Step-by-step explanation:

y = x     .....(1)

[tex]y=\sqrt{x}[/tex]     .... (2)

By solving equation (1) and equation (2)

[tex]x = \sqrt{x}[/tex]

[tex]\sqrt{x}\left ( \sqrt{x}-1 \right )=0[/tex]

[tex]\sqrt{x}=0[/tex] or [tex]\left ( \sqrt{x}-1 \right )=0[/tex]

x = 0, x = 1

y = 0, y = 1

A = [tex]\int_{0}^{1}ydx(curve)-\int_{0}^{1}ydx(line)[/tex]

A = [tex]\int_{0}^{1}\sqrt{x}dx-\int_{0}^{1}xdx[/tex]

A = [tex]\frac{2}{3}[x^\frac{3}{2}]_{0}^{1}-\frac{1}{2}[x^2]_{0}^{1}[/tex]

A = [tex]\frac{2}{3}-\frac{1}{2}[/tex]

A = [tex]\frac{1}{6}[/tex]

A house cleaning service claims that it can clean a four bedroom house in less than 2 hours. A sample of n = 16 houses is taken and the sample mean is found to be 1.97 hours and the sample standard deviation is found to be 0.1 hours. Using a 0.05 level of significance the correct conclusion is:(A) reject the null because the test statistic (-1.2) is < the critical value (1.7531).(B) do not reject the null because the test statistic (-1.2) is > the critical value (-1.7531).(C) reject the null because the test statistic (-1.7531) is < the critical value (-1.2).(D) do not reject the null because the test statistic (1.2) is > the critical value (-1.7531).

Answers

Answer:

Option B is right

Step-by-step explanation:

[tex]H_0: x bar =2\\H_a: x bar <2[/tex]

(One tailed test at 5% significance level)

n =16 and x bar =1.97

s =0.1

Std error of mean = [tex]\frac{s}{\sqrt{n} } \\=0.025[/tex]

Mean diff = [tex]1.97-2 =-0.03[/tex]

t statistic =Mean diff/se =-1.2

df =16-1=15

p value =0.124375

(B) do not reject the null because the test statistic (-1.2) is > the critical value (-1.7531).

Final answer:

The null hypothesis should not be rejected.

Explanation:

The question is asking whether to reject or not reject the null hypothesis based on the given information. The null hypothesis states that the house cleaning service can clean a four bedroom house in less than 2 hours. To test this hypothesis, a sample of 16 houses was taken, with a sample mean of 1.97 hours and a sample standard deviation of 0.1 hours. Using a significance level of 0.05, we compare the test statistic to the critical value to make the decision.

The correct conclusion in this case is to do not reject the null hypothesis, because the test statistic of -1.2 is greater than the critical value of -1.7531. Therefore, there is insufficient evidence to conclude that the cleaning service takes more than 2 hours to clean a four bedroom house.

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A sample of 9 production managers with over 15 years of experience has an average salary of $71,000 and a sample standard deviation of $18,000. Assuming that s = 18,000 is a reasonable estimate for f$sigma f$ what sample size would be needed to ensure that we could estimate the true mean salary of all production managers with more than 15 years experience within $4200 if we wish to be 95% confident? Place your answer, as a whole number, in the blank. Do not use a dollar sign, a comma, or any other stray mark. For examples, 34 would be a legitimate entry.

Answers

Answer:

The sample size to meet the 95% confidence and a maximum error of 4200 in the salary estimate, is 71

Step-by-step explanation:

You want to estimate the average salary of production managers with more than 15 years of experience, for this you will use a 95% confidence interval with a maximum estimation error of 4200.

[tex]\bar X = 71000\\\\\alpha = 0.05\\\\Z_{\frac{\alpha}{2}}=1.95996\\\\\sigma = 18000\\\\\epsilon=4200[/tex]

The expression for the calculation of the sample size is given by:

[tex]n= (\frac{\sigma Z_{\frac{\alpha}{2}}}{\epsilon})^2=(\frac{18000*1.95996}{4200})^2=70.5571[/tex]

You can use the margin of error formula to get  the needed sample size.

The needed sample size for the given condition is 71

What is the margin of error for large samples?

Suppose that we have:

Sample size n > 30Sample standard deviation = [tex]s[/tex]Population standard deviation = [tex]\sigma[/tex]Level of significance = [tex]\alpha[/tex]

Then the margin of error(MOE) is obtained as

Case 1: Population standard deviation is known

[tex]MOE = Z_{\alpha /2}\dfrac{\sigma}{\sqrt{n}}[/tex]

Case 2: Population standard deviation is unknown.

[tex]MOE = Z_{\alpha /2}\dfrac{s}{\sqrt{n}}[/tex]

where [tex]Z_{\alpha/2}[/tex] is critical value of the test statistic at level of significance  [tex]\alpha[/tex]

Using the above formula, we get the sample size needed as

Since the limit of error is $4200, thus,

MOE = $4200

The level of significance is [tex]\alpha[/tex] = 100 - 95% = 5% = 0.05

Critical value  [tex]Z_{\alpha/2}[/tex] at 0.05 level of significance for two tailed test is 1.96

The standard deviation estimate(sample standard deviation) is s= $18000, thus, we have:

[tex]MOE = Z_{\alpha /2}\dfrac{s}{\sqrt{n}}[/tex]

[tex]4200 = 1.96 \times \dfrac{18000}{\sqrt{n}}\\\\n = (\dfrac{35280}{4200})^2 = (8.4)^2 = 70.56[/tex]

Since MOE is inversely proportional to root of n, thus, we will take sample as 71 which will make MOE to be less than (or say within, as asked in problem) $4200.

Thus,

The needed sample size for the given condition is 71

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Two cars leave a city heading in the same direction. After 3 hours, the faster card is 9 miles ahead of the slower car. The slower car has traveled 153 miles. Find the speed of the two cars.

Answers

Answer:

The speed of the slower car is: 51 miles/hour and the speed of the faster car is 54 miles/hour.

Step-by-step explanation:

First, we can easily find the speed of the slower car, since we know that the speed is given by the formula v=d/t, where d stands for the traveled distance and t for the elapsed time.

[tex]v_{s}=\frac{d_{s}}{t}=\frac{153\ miles}{3\ hours} = 51\ miles/hour[/tex]

Next, for the faster car, we know that the distance traveled is 153+9 miles in the same time, therefore, its speed is given by:

[tex]v_{f}=\frac{d_{f}}{t}=\frac{153+9\ miles}{3\ hours} = 54\ miles/hour[/tex]

An intravenous solution contains 500 μg of a drug substance in each milliliter. How many milligrams of the drug would a patient receive from the intravenous infusion of a liter of the solution?

Answers

Answer:

The patient would receive 500mg from the intravenous infusion of a liter of the solution

Step-by-step explanation:

The problem states that an intravenous solution contains 500 μg of a drug substance in each milliliter. And asks how many milligrams of the drug would a patient receive from the intravenous infusion of a liter of the solution.

First step:

Conversion of 500ug to mg.

Each mg has 1,000ug. So

1mg - 1,000ug

xmg - 500ug

1,000x = 500

[tex]x = \frac{500}{1,000}[/tex]

x = 0.5mg

Each milliliter has 0.5mg. The problem asks how many milligrams of the drug would a patient receive from the intravenous infusion of a liter of the solution.

Each liter has 1000 milliliters. So, the problem asks how many miligrams of the drug would a patient receive from the intravenous infusion of 1000 mililiters of the solution. So

1mL - 0.5mg

1,000mL - xg

x = 0.5*1,000

x = 500mg

The patient would receive 500mg from the intravenous infusion of a liter of the solution

The patient receives 500 milligrams of the drug from an intravenous infusion of 1 liter, by converting 500 micrograms to milligrams and multiplying by 1000 milliliters.

To determine how many milligrams (mg) of the drug a patient would receive from an intravenous infusion of 1 liter (1000 milliliters) of the solution, we start with the given information that there are 500 micrograms (μg) of the drug per milliliter (mL) of the solution.

First, convert the amount of drug per milliliter from micrograms to milligrams.

Note that 1 milligram (mg) = 1000 micrograms (μg):

500 μg = 500 / 1000 mg500 μg = 0.5 mg

Now, calculate the total amount of drug in 1000 milliliters (since 1 liter = 1000 mL):

Total amount (mg) = 0.5 mg/mL * 1000 mLTotal amount (mg) = 500 mg

Thus, the patient would receive 500 mg of the drug from the intravenous infusion of 1 liter of the solution.

What is the area of a regular polygon with 16 sides and side length 4 inches? PLease explain in detail with a diagram. Thank You.

Answers

Answer:

Area is 321.6 square inches.

Step-by-step explanation:

A regular polygon with 16 sides is a Regular Hexadecagon. Regular means all sides are equal dimension. See image attached.

Side length is 4 inches.

side length=s=4 inches

You need to calculate the apothem.

Apothem=s*2.51367

Apothem=10.054

2.  You can use the formula to calculate de area of an hexadecagon:

[tex]A=\frac{Perimeter*Apothem}{2}[/tex]

Perimeter=16 sides*4inches

Perimeter= 64 inches

[tex]A=\frac{64*10.054}{2}[/tex]

[tex]A=321.6 inches^{2}[/tex]

An election forecasting model has a 50:50 chance of correctly predicting the election winner when there are two candidates. Before seeing the prediction of the model an election researcher estimates that there is a 75% chance that candidate Allan will defeat candidate Barnes. She then finds out that the model has predicted a victory for Barnes. Her posterior probability of a victory for Allan should be: (a) (b) (c) (d) 0.375 0.500 0.750 1.000

Answers

Answer:

Te correct answer is c) 0.750

Step-by-step explanation:

Lets call:

A = {Allan wins the election}

B = {Barnes wins the election}

MA = {the model predicts that Allan wins}

MB = {the model predicts Barnes wins}

We know that the model has a 50:50 chance of correctly predicting the election winner when there are two candidates. Then:

P(MA | A) = 0.5 = P(MA | B)

P(MB | B) = 0.5 = P(MB | A)

The prior probability P(A) given by the election researcher is 0.75

We must find the posterior probability P(A | MB)

We use Bayes theorem:

[tex]P(A|MB) = \frac{P(MB|A)P(A)}{P(MB)} = \frac{0.5*0.75}{0.5} = 0.75[/tex]

We used the result:

[tex]P(MB) = P(MB|A)P(A) + P(MB|B)P(B) = 0.5*0.75+0.5*0.25=0.5[/tex]

Given the statement "If I have the disease, then I will test positive." Show all work. (Discrete Mathematics)

a) Write the converse.

b) Write the inverse.

c) Write the contrapositive.

d) Write the statement as a disjunction.

e) Write the negation.

Answers

Answer with Step-by-step explanation:

We are given that a statement ''If I have the disease , then I will test positive.''

Let p:I have the disease.

q:I will test positive.

a.Converse :[tex]q\implies p[/tex]

''If I will test positive, then I have the disease''.

b.Inverse :[tex]\neg p\implies \neg q[/tex]

''If I have not the disease, then I will not test positive.''

c. Contrapositive:[tex]\neg q\implies \neg p[/tex]

''If I will not test positive, then I have not the disease''.

d.Disjunction:p or q=[tex]p\vee q[/tex]

''I have the disease or I will test positive''.

e.Negation :If p is true then its negation is p is false.

Negation of conditional statement is equivalent to [tex]p\wedge \neg q[/tex]

I have disease and I will not test positive.

Find the area of AABC. Where: A = (-3,3), B=(-4,1), C = (-6,0). W Area:

Answers

Answer: [tex]1.5\text{ square units}[/tex]

Step-by-step explanation:

We know that the area of triangle with coordinates [tex](x_1,y_1),(x_2,y_2)[/tex] and [tex](x_3,y_3)[/tex] is given by :-

[tex]\text{Area}=\dfrac{1}{2}|x_1(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)|[/tex]

Given : The coordinates of ΔABC are  A = (-3,3), B=(-4,1), C = (-6,0).

Then, the area of ΔABC will be :-

[tex]\text{Area}=\dfrac{1}{2}|-3(1-0)+(-4)(0-3)+(-6)(3-1)|\\\\\Rightarrow\text{Area}=\dfrac{1}{2}|-3-4(-3)-6(2)|\\\\\Rightarrow\text{Area}=\dfrac{1}{2}|-3+12-12|\\\\\Rightarrow\text{Area}=\dfrac{1}{2}|-3|=\dfrac{1}{2}(3)=1.5 [/tex]

Hence, the area of ΔABC= [tex]1.5\text{ square units}[/tex]

TRUE OR FALSE. World population growth is steady since prehistoric times and so the exponential growth model is applicable and accurate

Answers

i think the answer to your question is FALSE .

Final answer:

The statement is FALSE. Human population growth has experienced different rates and is not described accurately by an exponential growth model for all periods, with various factors affecting growth rates. Population is projected to stabilize in the future, not grow indefinitely.

Explanation:

The statement is FALSE. Human population growth has not been steady since prehistoric times. While it is true that the human population growth since 1000 AD has often exhibited exponential patterns, it has also undergone various phases and rates of growth due to many factors such as economics, wars, disease, technological advancement, and social changes. For instance, the population in Asia, which has many economically underdeveloped countries, is increasing exponentially. However, in Europe, where most countries are economically developed, population is growing much more slowly. Additionally, historic events like the Black Death and the World Wars caused noticeable dips in population growth. Hence, the exponential growth model does not accurately describe all periods in human history. Modern projections suggest that the world's population will stabilize between 10 and 12 billion, indicating that population growth will not continue exponentially indefinitely.

Some earlier descriptions of population growth suggested a more stable growth during early human history, with high birth and death rates. Over time and especially in the recent centuries, more data has allowed us to understand that the population growth has experienced different growth rates. The issue of ongoing exponential growth and its sustainability is a topic of significant debate, considering the finite resources of the planet and the impacts of overpopulation.

If the mass of your roommate is 150 lbm, what is his or her weight (lbf)?

Answers

Answer: Weight(lbf) = 4830

Step-by-step explanation:

Given :

Mass of the roommate = 150 lbm

Since we know that g = [tex]32.2 feet/s^{2}[/tex]

Therefore, we can calculate his/her weight in lbf using the following formula:

Weight(lbf) = Mass × g

Weight(lbf) = 150 × 32.2

Weight(lbf) = 4830

Cookies are sold singly or in packages of 7 or 21. With this packaging, how manyThere are ways can you buy 42 cookies? different ways to buy 42 cookie

Answers

Final answer:

There are 5 different ways to buy 42 cookies: three 21-cookie packages, two 21-cookie packages and one 7-cookie package, one 21-cookie package and three 7-cookie packages, one 21-cookie package, two 7-cookie packages, and one single, and three 7-cookie packages and seven singles.

Explanation:

To determine how many different ways you can buy 42 cookies, we can break it down into different combinations of packages. The packages are sold in singles, 7-cookie packages, and 21-cookie packages.

Let's start with the largest packages, the 21-cookie packages. We can buy zero, one, two, or three packages. For each number of packages, we can then calculate the number of remaining cookies we need to buy with singles and 7-cookie packages. We repeat this process for the 7-cookie packages, and then for the singles.

Using this method, we find that there are 5 different ways to buy 42 cookies:

Three 21-cookie packagesTwo 21-cookie packages and one 7-cookie packageOne 21-cookie package and three 7-cookie packagesOne 21-cookie package, two 7-cookie packages, and one singleThree 7-cookie packages and seven singles

A sonnet is a 14-line poem in which certain rhyming patterns are followed. The writer Raymond Queneau published a book containing just 10 sonnets, each on a different page. However, these were structured such that other sonnets could be created as follows: the first line of a sonnet could come from the first line on any of the 10 pages, the second line could come from the second line on any of the 10 pages, and so on (successive lines were perforated for this purpose).
(a) How many sonnets can be created from the 10 in the book?
(b) If one of the sonnets counted in part (a) is selected at random, what is the probability that none of its lines came from either the first or the last sonnet in the book? (Round your answer to three decimal places.)

Answers

Answer:

a) [tex]10^{14}[/tex]

b) 0.044

Step-by-step explanation:

Part a)

A Sonet is a 14-line poem. Raymond Queneau published a book containing just 10 sonnets, each on different pages. This means, on each page the writer wrote a 14-line poem. We have to find how many sonnets can be created from the 10 sonnets in the book.

Since, the first line of the new sonnet can be the first line of any of the 10 sonnets. So, there are 10 ways to select the first line. Similarly, the second line of the new sonnet can be the second line of any of the 10 sonnets. So, there are 10 ways to select the second line. Same goes for all the 14 lines i.e. there are 10 ways to select each of the line.

According to the fundamental principle of counting, the total number of possible sonnets would be the product of all the possibilities of all 14 lines.

So,

The number of sonnets that can be created from the book = 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = [tex]10^{14}[/tex] sonnets

So, [tex]10^{14}[/tex] can be created from the 10 in the book.

Part b)

First we need to find how many such sonnets can be created that have none of their lines from 1st and last page. Since, total number of pages is 10, if we are NOT to select from 1st and last page, this will leave us with 8 pages (8 sonnets).

So, now the number of possible options for each line of the sonnet would be 8. And according to the  fundamental principle of counting, the number of sonnets with neither the line from 1st nor the last page would be = [tex]8^{14}[/tex]

This represents the number of favorable outcomes, as we want the randomly selected sonnet to be such that none of its lines came from either the first or the last sonnet in the book.

So,

Number of favorable outcomes = [tex]8^{14}[/tex]

Total possible outcomes of the event = [tex]10^{14}[/tex]

As the probability is defined as the ratio of favorable outcomes to the total outcomes, we can write:

The probability that none of its lines came from either the first or the last sonnet in the book = [tex]\frac{8^{14}}{10^{14}} = 0.044[/tex]

You can use the product rule from combinatorics to calculate the number of ways sonnets can be created.

The answers are:

a) The number of sonnets that can be created are [tex]10^{14}[/tex]

b) The probability needed is 0.04398

What is the rule of product in combinatorics?

If a work A can be done in p ways, and another work B can be done in q ways, then both A and B can be done in  [tex]p \times q[/tex] ways.

Remember that this count doesn't differentiate between order of doing A first or B first then doing other work after the first work.

Thus, doing A then B is considered same as doing B then A

Now, each of the 14 lines of the sonnet we're going to create can be chosen from 10 of the sonnets available in book, thus, by using rule of product for these 14 events, each possible to be done in 10 ways, the total number of ways comes to be

[tex]10 \times 10 \times ... \times 10\: \: (14\rm \: times) = 10^{14}[/tex]sonnets.

Thus,

a) The number of sonnets that can be created are [tex]10^{14}[/tex]

Now, the number of ways we can select sonnet's lines such that it doesn't contain its lines from first or last sonnet can be calculated just as previous case but now there are only 8 options available for each line (as 2 of them are restricted from using).

Thus,

[tex]8 \times 8 \times ... \times 8\: \: (14\rm \: times) = 8^{14}[/tex]sonnets possible who doesn't contain any lines from first and last sonnet.

Let E be the event such that

E = Event of selecting sonnets which doesn't contain any line from first or last sonnet

Then,

[tex]P(E) = \dfrac{\text{Count of favorable cases}}{\text{Count of total cases}} = \dfrac{8^{14}}{10^{14}} = (0.8)^{14} \approx 0.04398[/tex]

Thus,

the probability that none of its lines came from either the first or the last sonnet in the book is 0.04398 approx.

Thus,

The answers are:

a) The number of sonnets that can be created are [tex]10^{14}[/tex]

b) The probability needed is 0.04398

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Use induction to prove that for all integers n 2 1 we have 1.1! +2.2! +3.3! + ... +nin! = (n + 1)! - 1.

Answers

Step-by-step explanation:

Let's assume that

P(n)=1.1! +2.2! +3.3! + ... +n.n! = (n + 1)! - 1.

For n = 1

L.H.S = 1.1!

         = 1

R.H.S = (n + 1)! - 1.

          =(1 + 1)! - 1.

          = 1

L.H.S = R.H.S

Hence the P(n) is true for n=1

Fort n = 2

L.H.S=1.1! +2.2!

        =1+4

        =5

R.H.S = (2 + 1)! - 1.

          =(2 + 1)! - 1.

          = 5

L.H.S = R.H.S

Hence the P(n) is true for n=2

Let's assume that P(n) is true for all n.

Then we have to prove that P(n) is true for (n+1) too.

So,

L.H.S = 1.1! +2.2! +3.3! + ... +n.n!+(n+1).(n+1)!

         = (n + 1)! - 1 +(n+1).(n+1)!

         = (n+1)![1+(n+1)]-1

         =(n+1)!(n+2)-1

         =(n+2)!-1

         =[(n+1)+1]!-1

So, P(n) is also true for (n+1).

So, P(n) is true for all integers n.

The returns from an investment are 4% in Year 1, 7% in Year 2, and 10.8% in the first half of Year 3. Calculate the annualized return for the entire period.

Answers

Final answer:

To calculate the annualized return of an investment with varying yearly returns, convert the percentage returns to decimal format, add 1, multiply them together, take the cube root (for a 3-year period), subtract 1 and convert back to a percentage. This provides a simplified approach to understanding how each year contributes to the overall growth, demonstrating the power of compound interest over time.

Explanation:

To calculate the annualized return for an investment over a multi-year period with varying yearly returns, you can use the formula for geometric mean. The returns provided are 4% in Year 1, 7% in Year 2, and 10.8% for the first half of Year 3. Since the return in Year 3 is only for half the year, we annualize this by considering the effective annual rate that would lead to this return over half a year, which could be simplified for calculation purposes here without altering the principle of geometric mean calculation for annualization. Assuming each return compounds, the computation involves converting the percentage returns to their decimal form, adding 1 to each (to account for the total value, not just the gain), multiplying these values together, then taking the cube root (since we're considering a period slightly over 2.5 years), and finally subtracting 1 and converting back to a percentage.

This simplifies to:
Annualized Return = ((1 + 0.04) * (1 + 0.07) * (1 + 0.108)) 1/3 - 1, which when solved gives the annualized return. However, correctly accounting for the exact duration (slightly over 2.5 years) could involve more precise financial formulas or software for exactitude.

It is crucial to recognize each year's return contributes to the calculation differently because of compound interest, which is why each year must be calculated based on its specific return, then all are combined to find the overall annualized performance of the investment.

4. Rephrase the following statements in standard "if.. then" form:

(a) "We are buying a new TV only if the old TV breaks down."

(b) "In the United States, a good credit score is necessary for obtaining a loan."

(c) Unless you make me a better offer, I will keep my current job.

(d) The observation of faster than light travel would be sufficient reason to question relativity theory.

Answers

Answer:

See step-by-step explanation.

Step-by-step explanation:

a) If the old TV breaks down then we are buying a new TV.

b) If you have a good credit score in the United States, then you obtain a loan.

c) If you don't make me a better offer then I will keep my current job.

d) If we observe faster than light travel then we would question relativity theory.

Final answer:

Conditional statements, often structured in "if... then" form, express logical relationships between propositions. The provided statements have been reformulated as clear conditionals, preserving their logical meaning.

Explanation:

The statements provided by the student can be rephrased in standard "if... then" form as follows:

If the old TV breaks down, then we are buying a new TV.If you want to obtain a loan in the United States, then a good credit score is necessary.If you do not make me a better offer, then I will keep my current job.If we observe faster than light travel, then that would be a sufficient reason to question relativity theory.

These rephrased statements maintain the same logical meaning but are now in the clear structure of conditionals that indicate a cause-and-effect relationship.

Find an equation of the line that contains the following pair of points (3,3) and (1,6) The equation of the line is (Simplify your answer. Use integers or fractions for any numbers in the equ

Answers

Answer:  [tex]\bold{y=-\dfrac{3}{2}x+\dfrac{15}{2}}[/tex]

Step-by-step explanation:

First, use the slope formula: [tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]

Then input the slope (m) and ONE of the points (x₁, y₁) into the

Point-Slope formula: y - y₁ = m(x - x₁)

[tex]m=\dfrac{3-6}{3-1}\quad =\dfrac{-3}{2}\quad \implies \quad m=-\dfrac{3}{2}\\\\\\\\y-3=-\dfrac{3}{2}(x-3)\\\\\\y-3=-\dfrac{3}{2}x+\dfrac{9}{2}\\\\\\y\quad =-\dfrac{3}{2}x+\dfrac{15}{2}[/tex]

what is the answer to - (4y - 8) + 11

Answers

Answer:

you would multiply the 11 so 88-44y tjen divide which is 22

Step-by-step explanation:

Answer:

19-4y

Step-by-step explanation:

-(4y-8)+11

-4y+8+11

it becomes - 4y and +8 because you multiply the - into the equation

-4y+19

19-4y

What does flipped E means and upside down A means in discrete math?

Answers

A backward e means "there exists".

An upside down A means "for all".

Final answer:

The flipped E symbol (∃) is used to assert that there exists at least one element in a set that satisfies a given property in discrete math. The upside-down A symbol (∀) is used to assert that all elements in a set satisfy a given property.

Explanation:

The flipped E and upside-down A are symbols used in discrete math to represent logical operations. The flipped E symbol (∃) is called the Existential Quantifier and is used to assert that there exists at least one element in a set that satisfies a given property. The upside-down A symbol (∀) is called the Universal Quantifier and is used to assert that all elements in a set satisfy a given property.



For example, if we have a set of integers S = {1, 2, 3, 4, 5}, the statement ∃x(x > 3) would be true because there exists at least one element in set S (in this case, 4 or 5) that is greater than 3. On the other hand, the statement ∀x(x > 3) would be false because not all elements in set S are greater than 3, as 1, 2, and 3 are also included in the set.

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