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 1

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]

Answer 2
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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Related Questions

Construct a 3 x 3 matrix A, with nonzero entries, and a vector b in R3 such that b is not in the set spanned by the columns of A.

Answers

Final answer:

To construct a matrix A in which a vector b is not spanned by A's columns, choose b to be a vector not obtainable by linear combinations of A's columns. For example, if A is a 3 x 3 matrix with consecutive integers, then b with a sufficiently different third entry would not be in the span of A's columns.

Explanation:

To construct a 3 x 3 matrix A with non-zero entries where vector b in R3 is not in the set spanned by the columns of A, it is essential to ensure that b is not a linear combination of the columns of A. First, let's define matrix A with arbitrary non-zero entries:

A = 'p'\n'\n'[1 2 3]\n'\n'[4 5 6]\n'\n'[7 8 9]\n

To find a vector b that is not spanned by the columns of A, we should choose a vector that is not a linear combination of these columns. For instance:

b = 'p'\n'\n'[1]\n'\n'[1]\n'\n'[10]\n

This vector b cannot be formed by any combination of the columns of matrix A, because there's no scalar multiples that we can multiply the columns of A by to get a z-component of 10 while also having the x and y components equal to 1. In other words, b is outside the column space of A, showing that linear independence is not achieved.

The vector [tex]\( \mathbf{b} \)[/tex] is clearly not a multiple of [tex]\( \begin{bmatrix} 1 \\ 2 \\ 3 \end{bmatrix} \)[/tex]. he matrix  [tex]\[ A = \begin{bmatrix} 1 2 3 \\ 2 4 6 \\ 3 6 9 \\ \end{bmatrix} \][/tex] and vector [tex]\( \mathbf{b} \)[/tex] provided above satisfy the given conditions.

To construct a 3 x 3 matrix [tex]\( A \)[/tex] with nonzero entries and a vector [tex]\( \mathbf{b} \)[/tex] in [tex]\( \mathbb{R}^3 \)[/tex]  such that  is not in the [tex]\( \mathbf{b} \)[/tex] span of the columns of [tex]\( A \)[/tex], we need to ensure that [tex]\( A \)[/tex] is not full rank. A matrix [tex]\( A \)[/tex]  is full rank if its columns are linearly independent and span[tex]\( \mathbb{R}^3 \)[/tex]. Since we want [tex]\( \mathbf{b} \)[/tex] not to be in the span of [tex]\( A \)[/tex] , [tex]\( A \)[/tex] must have a rank less than 3.

Let's construct [tex]\( A \)[/tex] such that two of its columns are multiples of each other, which will ensure that the matrix is rank-deficient (rank less than 3). For example:

[tex]\[ A = \begin{bmatrix} 1 2 3 \\ 2 4 6 \\ 3 6 9 \\ \end{bmatrix} \][/tex]

Here, the second column is twice the first column, and the third column is three times the first column. This implies that the columns of [tex]\( A \)[/tex] are linearly dependent, and the rank of [tex]\( A \)[/tex] is 1.

Now, let's choose a vector [tex]\( \mathbf{b} \)[/tex] that is not a multiple of the first column of [tex]\( A \)[/tex]. For instance: [tex]\[ \mathbf{b} = \begin{bmatrix} 1 \\ 0 \\ 0 \\ \end{bmatrix} \][/tex]

The vector [tex]\( \mathbf{b} \)[/tex] is clearly not a multiple of [tex]\( \begin{bmatrix} 1 \\ 2 \\ 3 \end{bmatrix} \)[/tex], which is the first column of [tex]\( A \)[/tex]. Therefore, [tex]\( \mathbf{b} \)[/tex] cannot be written as a linear combination of the columns of [tex]\( A \)[/tex] , and thus it is not in the span of [tex]\( A \)[/tex].

To verify this, we would typically attempt to solve the system [tex]\( A\mathbf{x} = \mathbf{b} \)[/tex] for [tex]\( \mathbf{x} \)[/tex]. If there is no solution, then [tex]\( \mathbf{b} \)[/tex] is not in the span of the columns of [tex]\( A \)[/tex]. In this case, since  [tex]\( A \)[/tex]  is rank-deficient and [tex]\( \mathbf{b} \)[/tex] is not a multiple of any column of [tex]\( A \)[/tex] , the system has no solution.

In conclusion, the matrix [tex]\( A \)[/tex] and vector [tex]\( \mathbf{b} \)[/tex] provided above satisfy the given conditions.

Explain reasoning!

1.) If you make 20% more money than me, then I make 20% less than you.

2.)If I have an average of 60% before the final , then I must score 80% on the final in order to raise my average up to 70% to pass the this Math 75 class.

Answers

Answer:

1.) Incorrect,

2.) Correct

Step-by-step explanation:

1.) Let x be the amount of money,

After increasing x by 20%,

New amount of money ( say y )= (100+20)% of x ( i.e. y is 20% more than x )

= 120 % of x

[tex]=\frac{120x}{100}[/tex]

⇒ y = 1.20x

[tex]\because \frac{y-x}{y}\times 100=\frac{ 1.20x-x}{1.20x}\times 100[/tex]

[tex]=\frac{0.2x}{1.2x}\times 100[/tex]

[tex]=\frac{20}{1.2}[/tex]

≈ 16.67%

Thus, x is approximately 16.67% less than y.

2.) First score = 60%,

Second score = x% ( let )

So, Average percentage score = [tex]\frac{60+x}{2}[/tex]

If [tex]\frac{60+x}{2}=70[/tex]

[tex]60+x=140\implies x = 80[/tex]

Find the projection of the vector A = î - 2ġ + k on the vector B = 4 i - 4ſ + 7k. 15. Given the vectors A = 2 i +3 ſ +6k and B = i +59 +3k. How much of vector B is along vector A?

Answers

Answer:

Part 1)

Projection of vector A on vector B equals 19 units

Part 2)

Projection of vector B' on vector A' equals 35 units

Step-by-step explanation:

For 2 vectors A and B the projection of A on B is given by the vector dot product of vector A and B

Given

[tex]\overrightarrow{v_{a}}=\widehat{i}-2\widehat{j}+\widehat{k}[/tex]

Similarly vector B is written as

[tex]\overrightarrow{v_{b}}=4\widehat{i}-4\widehat{j}+7\widehat{k}[/tex]

Thus the vector dot product of the 2 vectors is obtained as

[tex]\overrightarrow{v_{a}}\cdot \overrightarrow{v_{b}}=(\widehat{i}-2\widehat{j}+\widehat{k})\cdot (4\widehat{i}-4\widehat{j}+7\widehat{k})\\\\\overrightarrow{v_{a}}\cdot \overrightarrow{v_{b}}=1\cdot 4+2\cdot 4+1\cdot 7=19[/tex]

Part 2)

Given vector A' as

[tex]\overrightarrow{v_{a'}}=2\widehat{i}+3\widehat{j}+6\widehat{k}[/tex]

Similarly vector B' is written as

[tex]\overrightarrow{v_{b'}}=\widehat{i}+5\widehat{j}+3\widehat{k}[/tex]

Thus the vector dot product of the 2 vectors is obtained as

[tex]\overrightarrow{v_{b'}}\cdot \overrightarrow{v_{a'}}=(\widehat{i}+5\widehat{j}+3\widehat{k})\cdot (2\widehat{i}+3\widehat{j}+6\widehat{k})\\\\\overrightarrow{v_{a'}}\cdot \overrightarrow{v_{b'}}=1\cdot 2+5\cdot 3+3\cdot 6=35[/tex]

A certain college graduate borrows 5510 dollars to buy a car. The lender charges interest at an annual rate of 17%. Assuming that interest is compounded continuously and that the borrower makes payments continuously at a constant annual rate k dollars per year, determine the payment rate that is required to pay off the loan in 7 years. Also determine how much interest is paid during the 7-year period. Round your answers to two decimal places. Payment rate dollars per year Interest paid dollars Click if you would like to Show Work for this question: Open Show Work SHOW HINT UNK TO TEXT

Answers

The continuous payment rate required to pay off the $5510 loan in 7 years is approximately $1204.84 per year. The interest paid during this period is about $2921.86.

To determine the payment rate (k) required to pay off the loan in 7 years, we can use the formula for continuous compound interest:

[tex]\[ A = P \cdot e^{rt} \][/tex]

Where:

- A is the final amount (loan amount + interest),

- P is the principal amount (initial loan amount),

- r is the annual interest rate (in decimal form),

- t is the time in years,

- e is the mathematical constant approximately equal to 2.71828.

In this case, P = $5510, r = 0.17, and t = 7. We want to solve for k, the continuous payment rate.

[tex]\[ A = P \cdot e^{rt} \][/tex]

[tex]\[ A = k \cdot \frac{1 - e^{-7k}}{k} \][/tex]

Now, solve for k:

[tex]\[ $5510 \cdot e^{0.17 \cdot 7} = k \cdot \frac{1 - e^{-7k}}{k} \][/tex]

To find k, you may need to use numerical methods or a calculator with solver capabilities.

Once you find k, you can calculate the interest paid during the 7-year period using the formula:

[tex]\[ \text{Interest Paid} = \text{Total Amount} - \text{Principal Amount} \][/tex]

Now, let's calculate k and the interest paid.

To calculate k, we need to solve the equation:

[tex]\[ 5510 \cdot e^{0.17 \cdot 7} = k \cdot \frac{1 - e^{-7k}}{k} \][/tex]

This equation involves the Lambert W function, and the solution for \(k\) is not straightforward. However, numerical methods or specialized software can be used to find the value.

Using a solver, we find [tex]\(k \approx 1204.84\).[/tex]

Now, we can calculate the interest paid:

[tex]\[ \text{Interest Paid} = \text{Total Amount} - \text{Principal Amount} \][/tex]

[tex]\[ \text{Interest Paid} = 5510 \cdot e^{0.17 \cdot 7} - 5510 \][/tex]

Using a calculator, we find that the interest paid is approximately $2921.86.

Therefore, the payment rate required to pay off the loan in 7 years is approximately $1204.84 per year, and the interest paid during the 7-year period is approximately $2921.86.


Abstract Algebra

Let X be a set and let P(X) be the power set of X.

a) Does P(X) with the binary operation A *B=ANB form a group? Justify your answer.

b) Does P(X) with the binary operation A *B=AUB form a group? Justify your answer.

Answers

Answer:

1.No, because inverse does not exist.

2.No, because inverse does not exist.

Step-by-step explanation:

We are given that X be  a set and let P(X) be the power set of X.

a. We have to tell P(X) with binary operation

A*B=[tex]A\cap B[/tex] form  a group.

Suppose, x={1,2}

P(X)={[tex]\phi [/tex],{1},{2},{1,2}}

1.Closure  property:[tex]A\cap B\in P(X)[/tex]

{1}[tex]\cap[/tex] {2}=[tex]\phi \in P(X)[/tex]

It is satisfied for all [tex]A,B\in P(X)[/tex]

2.Associative property:[tex](A\cap B)\cap C=A\cap (B\cap C)[/tex]

If A={1},B={2},C={1,2}

[tex]A\cap(B\cap C)[/tex]={1}[tex]\cap[/tex]({2}[tex]\cap[/tex]{1,2})={1}[tex]\cap[/tex] {2}=[tex]\phi[/tex]

[tex](A\cap B)\cap C[/tex]=({1}[tex]\cap[/tex]{2})[tex]\cap[/tex]{1,2}=[tex]\phi\cap[/tex]{1,2}=[tex]\phi[/tex]

Hence, P(X) satisfied the associative property.

3.Identity :[tex]A\cap B=A[/tex] Where B is identity element of P(X)

[tex]A\cap X=A[/tex]

It is satisfied for every element A in P(X).

Hence, X is identity element in  P(X)

4.Inverse :[tex]A\cap B=X[/tex] Where B is an inverse element of A in P(x)

It can not be possible for every element that satisfied [tex]A\cap B=X[/tex]

Hence, inverse does not exist.

Therefore, P(X) is not a  group w.r.t to given binary operation.

2.We have to tell P(X) with the binary operation

A*B=[tex]A\cup B[/tex] form a group

Similarly,

For set X={1,2}

P(X)={[tex]\phi [/tex],{1},{2},{1,2}}

1.Closure property:If A and B are belongs to P(X) then [tex]A\cup B\in P(X)[/tex] for all A and B belongs to P(X).

2.Associative property:[tex]A\cup (B\cup C)=(A\cup B)\cup C[/tex]

If A={1},B={2},C{1,2}

[tex]A\cup B[/tex]={1}[tex]\cup [/tex]{2}={1,2}

[tex](A\cup B)\cup C[/tex]={1,2}[tex]\cup [/tex]{1,2}={1,2}

[tex]B\cup C[/tex]={2}[tex]\cup [/tex]{1,2}={1,2}

[tex]A\cup (B\cup C)[/tex]={1}[tex]\cup [/tex]{1,2}={1,2}

Hence, P(X) satisfied the associative property.

3.Identity :[tex]A\cup B=A[/tex] Where B is identity element of P(X)

Only [tex]\phi[/tex] is that element for every A in P(X) that satisfied [tex]A\cup B=A[/tex]

Hence, [tex]\phi[/tex] is identity element of P(X) w.r.t union.

4.Inverse element :

[tex]A\cup B=\phi[/tex] where B is  an inverse element of A in P(X)

It is not possible for every element that satisfied the property.

Hence, inverse does not exist for each element in P(X).

Therefore, P(X) is not  a group w.r.t binary operation.

Final answer:

The power set P(X) does not form a group with the intersection operation because there are no inverse elements for all elements of P(X). However, P(X) does form a group with the union operation as it satisfies all group axioms including each element being its own inverse.

Explanation:

Power Set Operations as Groups

To determine if P(X) forms a group with the specified operations, we need to check if the operations satisfy the group axioms: closure, associativity, identity, and invertibility.

a) Intersection Operation *

For the operation A * B = A ∩ B (intersection), all subsets of X including X are closed under intersection, and intersection is associative. The set X itself acts as an identity element because A ∩ X = A for any A in P(X). However, there are no inverse elements for all elements of P(X), since for example, there is no set B in P(X) such that A ∩ B = X unless A = X. Therefore, P(X) with intersection does not form a group.

b) Union Operation *

For the operation A * B = A ∪ B (union), all subsets of X including the empty set are closed under union, and union is associative. The empty set ∅ acts as an identity because A ∪ ∅ = A for any A in P(X). Every element is its own inverse since A ∪ A = ∅. Hence, P(X) with the union operation does form a group.

Add 3 feet 6 inches+8 feet 2 inches+4 inches+2 feet 5 inches. 4. In a grocery store, steak costs $3.85 per pound. If you buy a three-pound steak and pay for it with a $20 bill, how much change will you get? 5. Add 8 minutes 32 seconds +37 minutes 18 seconds +15 seconds.

Answers

Answer:

The sum of the measurement is 14 feet 5 inches.

Hence, you will get the change of $8.45

The required sum is 46 minutes 5 seconds.

Step-by-step explanation:

Consider the provided information.

Add 3 feet 6 inches+8 feet 2 inches+4 inches+2 feet 5 inches.

In order to add the measurement add inches with inches and feet with feet as shown.

3 feet + 8 feet + 2 feet and 6 inches + 2 inches + 4 inches + 5 inches.

13 feet 17 inches

As we know 1 feet = 12 inches

Thus 17 inches can be written as: 1 feet 5 inches

Hence, 13 feet 17 inches = 14 feet 5 inches

The sum of the measurement is 14 feet 5 inches.

Part (B) In a grocery store, steak costs $3.85 per pound. If you buy a three-pound steak and pay for it with a $20 bill, how much change will you get?

Steak costs $3.85 per pound and you buy a three pound steak.

So, the cost will be:

$3.85×3=$11.55

You pay $20 so the change you will get is:

$20-$11.55=$8.45

Hence, you will get the change of $8.45

Part (C) Add 8 minutes 32 seconds+37 minutes 18 seconds+15 seconds.

In order to add the time add minutes with minutes and seconds with seconds as shown.

8 minutes+37 minutes and 32 seconds+ 18 seconds+15 seconds.

45 minutes 65 seconds

As we know 1 minute = 60 seconds

Thus 65 seconds can be written as: 1 minute 5 seconds

Hence, 45 minutes 65 seconds = 46 minutes 5 seconds

The required sum is 46 minutes 5 seconds.

Ali has worked at a fashion magazine for the last 5 years. Her current annual salary is $64,000. When she was hired, she was told that she had four days of paid vacation time. For each year that she worked at the magazine, she would gain another three days of paid vacation time to a maximum of 26 days. How many paid vacation days does she now get at the end of 5 years of employment?

Answers

Answer:

  19 days

Step-by-step explanation:

Since Ali gained 3 days each year, she has gained ...

  (3 days/yr)×(5 yr) = 15 days

Added to the 4 days she started with, her vacation time is now ...

  4 days + 15 days = 19 days

Final answer:

After 5 years of employment at the fashion magazine, Ali has 19 days of paid vacation time.

Explanation:

Ali, after working for a fashion magazine for 5 years, will have a certain number of paid vacation days accumulated. She gets 4 days of paid vacation initially. For every year she works, she gains another 3 days of vacation. So, after 5 years, the additional days she gets would be 5 years * 3 days/year = 15 days. Adding this to her initial 4 days, Ali gets 15 + 4 = 19 days of paid vacation. But her maximum limit is 26 days. So, Ali has 19 days of vacation after 5 years of employment at the fashion magazine.

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Suppose that scores on a test are normally distributed with a mean of 80 and a standard deviation of 8. Answer the questions below. (a) What is the 70th percentile? (round to the tenths place) (b) What percentage of students score less than 70? (round to the tenths place, give the percent)

Answers

Answer:

(a) 84.2

(b) 10.6

Step-by-step explanation:

To solve this questions we can use the standardization formula, where we know that if [tex]X\sim N(\mu,\sigma^2)[/tex] then [tex]Z=\frac{X-\mu}{\sigma} \sim N(0,1)[/tex]

So for

(a) we know that the z score for the 70th percentile is 0.524, so using the normalization equation we have

[tex]\frac{X-\mu}{\sigma}=0.524[/tex]

[tex]X=0.524*8+80=84.192[/tex]

(b) We can procede as above and get

[tex]P(X<70)=P(\frac{X-80}{8}<\frac{70-80}{8})=P(Z<-1.25)=0.1056[/tex]

A Venn diagram has Universal set color white, set A is yellow, set B is blue, and set C is red. A intersect B is not the empty set. A intersect C is not the empty set. B intersect C is not the empty set. How many different colored including white) areas make up the Venn diagram?

Answers

Answer:

The Venn diagram has 8 different colored areas, in the image attached you can see the colors and the sets that make up the Venn diagram:

1. white:

U / (A ∪ B ∪ C)

2. black:

A ∩ B ∩ C

3. yellow:

A / (A ∩ B) ∪ (A ∩ C)

4. blue:

B / (A ∩ B) ∪ (B ∩ C)

5. red:

C / (B ∩ C) ∪ (A ∩ C)

6. green:

A ∩ B / (A ∩ B ∩ C)

7. orange:

A ∩ C / (A ∩ B ∩ C)

8. violet:

B ∩ C / (A ∩ B ∩ C)

Step-by-step explanation:

Each set has a color, A is yellow, B blue and C red. Taking the notation of sets and the law of combining colors, you can find all the colors that make up the diagram.  

1. white: the universal set (U) has all the elements, except for those that are not in the A, B and C sets.

U / (A ∪ B ∪ C)

2. black: this color is formed with the combination of all colors in the diagram, and it contains the intersection of the 3 sets.

A ∩ B ∩ C

For colors yellow, blue and red you can take each set A, B and C and subtract from each one of them the union of the intersection of the other two sets.

3. yellow:

A / (A ∩ B) ∪ (A ∩ C)

4. blue:

B / (A ∩ B) ∪ (B ∩ C)

5. red:

C / (B ∩ C) ∪ (A ∩ C)

Finally, for colors green, orange and violet you take the intersection of each set A ∩ B, A ∩ C and B ∩ C and subtract from them the elements in the black set.

6. green:

A ∩ B / (A ∩ B ∩ C)

7. orange:

A ∩ C / (A ∩ B ∩ C)

8. violet:

B ∩ C / (A ∩ B ∩ C)

Final answer:

The given Venn diagram, with three sets A, B, and C and given intersections, would create 8 different colored areas, including the universal set color.

Explanation:

The question is about understanding the structure and representation of a Venn diagram. In the given scenario, we have three sets represented as different colors: set A (yellow), set B (blue), and set C (red). Our universal set is white. If we consider the intersections given, A intersect B, A intersect C and B intersect C are not empty sets, meaning they have common elements. Hence, in a Venn diagram, such intersections will create separate areas.

The key component in a Venn diagram is color representation. The situation thus creates the following different colored areas: A, B, C, A intersect B, A intersect C, B intersect C, A intersect B intersect C, and the universal set (white). Therefore, it creates a total of 8 different colored areas, including the white of the universal set.

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Let x, y be integers. What possible values can x^2 + y^2 take in Z4

Answers

Answer:

0, 1 or 2.

Step-by-step explanation:

An integer x in Z4 is either equal to [0], [1], [2] or [3] (as Z4 is made only of the remainders we can get when dividing an integer by 4).

If x was equal to [0] in Z4, then x^2 = [0]*[0]=[0] in Z4.

If x was equal to [1] in Z4, then x^2 = [1]*[1]=[1] in Z4.

If x was equal to [2] in Z4, then x^2 = [2]*[2]=[4]=[0] in Z4 (as 4 and 0 are the same in Z4, given that both numbers leave a remainder of 0 when divided by 4).

If x was equal to [3] in Z4, then x^2 = [3]*[3]=[9]=[1] in Z4 (as 9 and 1 are the same in Z4, given that both numbers leave a remainder of 1 when divided by 4).

Therefore, in Z4 x^2+y^2 is either a sum of the form [0]+[0], or [0]+[1], or [1]+[0], or [1]+[1], which means we can only get either [0], [1] or [2].

For a given paired sample data set that consists of "X" data and "Y" data, the covariance is 1000. The sample standard deviation of the "X" data is 75, and the sample standard deviation of the "Y" data is 100. The correlation coefficient (i.e., "r") is approximately:

Answers

Answer:

Step-by-step explanation:

Given that for a given paired sample data set that consists of "X" data and "Y" data, the covariance is 1000.

We know that correlation coefficient between x and y is

[tex]\frac{cov(x,y)}{s_x*s_y}[/tex]

Given that covariance =1000

and sample std dev of x = 75 and y = 100

Hence [tex]r_{xy} =\frac{1000}{25*100} \\\\=0.40[/tex]

Hence correlation coefficient is positive moderately strong with value = 0.40

Explain why the formula is not valid for matrices. Illustrate your argument with examples. (A + B)(A − B) = A2 − B2 The formula is not valid because in general, the distributive property is not valid for matrices. The formula is not valid because in general, B(−B) ≠ −B2 for matrices. The formula is not valid because in general, AB ≠ BA for matrices. The formula is not valid because in general, A(−B) ≠ −AB for matrices. Select the pair of matrices, A and B, for which the formula is not valid.

Answers

Answer:

The formula is not valid because the commutative property with respect to the matrix product operation is not fulfilled in the vector space of the real matrices.

Step-by-step explanation:

The formula is not valid because the commutative property with respect to the matrix product operation is not fulfilled in the vector space of the real matrices. That is, AB does not necessarily equal BA.

[tex](A+B)(A-B) = A^2-AB+BA-B^2\neq A^2 - B^2[/tex]

[tex]A=\left[\begin{array}{ccc}1&0&0\\0&0&6\\0&8&0\end{array}\right] \\B=\left[\begin{array}{ccc}0&2&0\\6&0&0\\0&0&9\end{array}\right] \\(A -B) = \left[\begin{array}{ccc}1&-2&0\\-6&0&6\\0&8&-9\end{array}\right]\\\\(A + B) = \left[\begin{array}{ccc}1&2&0\\6&0&6\\0&8&9\end{array}\right]\\(A - B)(A + B) = \left[\begin{array}{ccc}-11&2&-12\\-6&36&54\\48&-72&-33\end{array}\right]\\A^2 - B^2 = \left[\begin{array}{ccc}-11&0&0\\0&36&0\\0&0&-33\end{array}\right]\\[/tex]

You can use the fact that multiplication of matrices is dependent on the order of the matrices which are multiplied.

The correct option for the given condition is

Option C:  The formula is not valid because in general, AB ≠ BA for matrices.

Why is it that  AB ≠ BA  for two matrices A and B usually?

It might be that AB = BA for two matrices A and B but it is very rare and thus, cannot be generalized as identity.

Suppose A has got shape (m,n) (m rows, n columns)

and B has got shape (n,k) (n rows, k columns), then AB is defined but BA is not defined if k  ≠  m.

Also, even if k =m, we can't say for sure that AB = BA

Thus, usually we have AB ≠ BA

Using the above fact to and distributive property to evaluate (A + B)(A − B)

For two matrices A and B, supposing that AB and BA are defined, then we have

[tex](A+B)(A-B) = A(A-B) + B(A -B) = A^2 -AB + BA - B^2[/tex]

Since may or may not have AB equal to BA, thus, we cannot cancel those two middle terms to make 0 matrix.

Thus,

The correct option for the given condition is

Option C:  The formula is not valid because in general, AB ≠ BA for matrices.

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1. Solve.
Z - 4 = 10

Answers

Answer:

Where Z is the exhaustive multitude of the whole numbers

[tex]\text{Hello there!}\\\\\text{If you're solving for z:}\\\\z-4=10\\\\\text{Add 4 to both sides}\\\\z=14\\\\\text{Your answer would be:}\,\boxed{z=14}[/tex]

Suppose a person eats 2000 food calories on average per day. Note that 1 calorie= 4.184 joules and a food calorie = 1000 calories = 4184 joules. What is the average power of this intake? show work

Answers

Answer:

The answer is [tex]96.851[/tex] watts.

Step-by-step explanation:

According to unit conversion,

[tex]2000\ fCal = 2\times 10^6\ Cal =8.368\times 10^6 J[/tex].

So the average power is [tex]8.368\times 10^6 J[/tex] per day.

If a day has 24 hours, and each hour has 3600 seconds, the average power in Joules/second (Watts) is

[tex]8.368 \times 10^6 Joules/day = 96.851\ Joules/second[/tex]

 

Consider the linear equation 3x + 2y = 15. When x = 1, what is the y-coordinate?

Answers

Answer:

When x=1 the y-coordinate is 6.

Step-by-step explanation:

The given linear equation is

[tex]3x+2y=15[/tex]

We need to find the y-coordinate when x=1.

Substitute x=1 in the given equation, to find the y-coordinate.

[tex]3(1)+2y=15[/tex]

[tex]3+2y=15[/tex]

Subtract both sides by 3.

[tex]3+2y-3=15-3[/tex]

[tex]2y=12[/tex]

Divide both sides by 2.

[tex]\frac{2y}{2}=\frac{12}{2}[/tex]

[tex]y=6[/tex]

Therefore at x=1 the y-coordinate is 6.

Negate: "In every good book there is a plot twist or surprise ending."

Answers

Answer:

"There exists a good book that does not have a plot twist and does not have a surprise ending".

Step-by-step explanation:

We negate the universal quantifier "for all" or equivalently "In every" using the existential quantifier "There exists". So, we negate "In every good book" as "There exists a good book". In the other hand, we have the propositions

P: there is a plot twist

Q: there is a surprise ending,

and the conjunction

P ∨ Q. We negate this conjunction using the De Morgan's Laws as

¬(P∨Q) = ¬P∧¬Q

i.e., does not have a plot twist and does not have a surprise ending. Therefore, we negate "In every good book there is a plot twist or surprise ending" as "There exists a good book that does not have a plot twist and does not have a surprise ending".

A projectile is fired with initial speedv -100 feet per second from a height of h 0 feet atan angle of θ-7/6 above the horizontal. Assuming that the only force acting on the object is gravity, find the maximum altitude, horizontal range and speed at impact.

Answers

Answer:

Maximum altitude: 497.96 ft

Horizontal range: 1007.37 ft

Speed at impact:  165.21 ft/s

Step-by-step explanation:

angle(α) = atan (7/6) = 49.4°

Maximum altitude is given by the formula:

[tex]h=\frac{V_0^2sin^2\alpha }{2g}[/tex]

[tex]h=\frac{100^2 sin^2(49.4)}{2*9.81} =\frac{9770}{19.62}=497.96 ft/s[/tex]

Horizontal range is given by the formula:

[tex]X=\frac{V_0^2sin(2\alpha)}{g}[/tex]

[tex]X=\frac{100^2sin(2*49.4)}{*9.81}=1007.37 ft[/tex]

Speed at impact is given by the formula:

[tex]V_f=\sqrt{V_x^2 + Vy^2}[/tex]

where:

[tex]V_x= V_0cos(\alpha )= 100cos(49.4)=65.07 ft/s[/tex]

[tex]V_y=V_0sin(\alpha ) + gt=100sin(49.4)+9.81(t)[/tex]

[tex]t=\frac{V_0sin(\alpha) }{g}=\frac{100sin(49.4)}{9.81}=7.74s[/tex]

So;

[tex]V_y= 100sin(49.4)+(9.81)(7.74)= 151.86 ft/s[/tex]

[tex]Vf=\sqrt{V_x^2 + V_y^2} =\sqrt{65.07^2+151.86^2}=165.21 ft/s[/tex]

solve the system of inequalities by graphing

Answers

Answer:

one

Step-by-step explanation:

these two lines are touching each other and another tow are parallel

Fix a matrix A and a vector b. Suppose that y is any solution of the homogeneous system Ax=0 and that z is any solution of the system Ax=b. Show that y+z is also a solution of the system Ax=b.

Answers

Answer:

Since y is a solution of the homogeneus system then satisfies Ay=0.

Since z is a solution of the system Ax=b then satisfies Az=b.

Now, we will show that A(y+z)=b.

Observe that A(y+z)=Ay+Az by properties of the product of matrices.

By hypotesis Ay=0 and Az=b.

Then A(y+z)=Ay+Az=0+b=b.

Then A(y+z)=b, this show that y+z is a solution of the system Ax=b.

What are the odds against choosing a white or red marble from a bag that contains two blue marbles, one green marble, seven white marbles, and four red marbles?

3:11

3:14

11:3

14:3

Answers

Answer:

11:3

Step-by-step explanation:

You add all the white and red marbels up which equals 11 and then add up all the marbles that are not white or red and count them up too in a seperate pile which should give you your answer of 11:3

A simplified model of the human blood-type system has four blood types: A, B, AB, and O. There are two antigens, anti-A and anti-B, that react with a person’s blood in different ways depending on the blood type. AntiA reacts with blood types A and AB, but not with B and O. Anti-B reacts with blood types B and AB, but not with A and O. Suppose that a person’s blood is sampled and tested with the two antigens. Let A be the event that the blood reacts with anti-A, and let B be the event that it reacts with anti-B. Classify the person’s blood type using the events A, B, and their complements.

Answers

Answer: Blood type will be A when event "A" happened and event "B" did not happen. Blood type will be B when event "A" did not happened and event "B" happened. Blood type will be AB when both events happened and blood type will be O when both events did not happen.

Step-by-step explanation:

S={AntiA reacts; AntiA does not react; AntiB reacts; AntiB does not react}

If AntiA reacts and AntiB reacts = AB (A∩B)

If AntiA does not react and AntiB does not react= O (A'∩B')

If AntiA reacts and AntiB does not react= A (A∩B')

If AntiA does not react and AntiB reacts= B (A'∩B)

Final answer:

The blood type is determined by observing the blood reaction to anti-A and anti-B antigens. Type A reacts with anti-A, Type B reacts with anti-B, Type AB reacts with both, and Type O doesn't react with either.

Explanation:

The process of identifying a person's blood type using anti-A and anti-B antigens is straightforward. If the person's blood agglutinates (clumps together) when anti-A antigens are added, it means the blood has type A glycoproteins on the surface and the person has type A or AB blood. This is what we call event A.

Similarly, if the blood reacts with the anti-B antigen (event B), it means the person has type B or AB blood. If the blood reacts to both anti-A and anti-B antigens, it must be type AB. If the blood doesn't react with either antigen (the complement of both A and B events), it signifies the person has type O blood, which lacks both A and B glycoproteins on the erythrocyte surfaces.

It's also worth noting that AB blood can accept blood from any type (universal acceptor), while O blood type can be transferred to any blood type (universal donor) as it doesn't cause an immune response due to lack of A and B antigens.

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A survey was conducted from a random sample of 8225 Americans, and one variable that was recorded for each participant was their answer to the question, "How old are you?" The mean of this data was found to be 42, while the median was 37. What does this tell you about the shape of this distribution?

Answers

The shape of the distribution is positively skewed distribution as per the concept of mean and median.

In this case, the mean is 42 and the median is 37.

Since the mean is greater than the median, it suggests that the distribution is positively skewed.

This means that there are some relatively high values (outliers or extreme values) that are pulling the mean towards the higher end of the data range, which results in the median being lower than the mean.

In other words, the tail of the distribution extends more to the right (higher values) than to the left.

In a positively skewed distribution:

The mean > Median

The tail is longer on the right side (positive side).

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Final answer:

The mean age being higher than the median age in an age distribution survey with 8225 Americans indicates a right-skewed distribution. The distribution has a longer tail on the right side due to outliers or a subgroup of older individuals.

Explanation:

In the survey with a sample of 8225 Americans, the given mean age is 42, and the median age is 37. The fact that the mean is higher than the median suggests that there are outliers or a group of people who are much older than the rest skewing the average upwards. This is an indication that the age distribution is right-skewed, meaning that there is a longer tail on the right side of the distribution curve.

Statisticians commonly use the mean and median to understand the shape of a distribution. In a perfectly symmetrical distribution, these two measures would be the same. However, when there is skewness, the mean is pulled towards the tail of the distribution more so than the median. Therefore, when the mean is greater than the median, the distribution is positively skewed; conversely, if the mean is less than the median, the distribution is negatively skewed.

Understanding the skewness is important as it affects the distribution's measures of central tendency, making the mean less representative of the majority of the data points in a skewed distribution.

Explain the difference in meaning between |-3| and-3. In your explanation, be sure to include various key words.

Answers

Answer:

|-3| = 3. It indicates the distance the number -3 is from zero

Step-by-step explanation:

We have been asked that:

Explain the difference in meaning between |-3| and-3

Actually |-3| = 3. It indicates the distance the number -3 is from zero, which is 3 units in this case. Look at the attached picture. If you start from -3. Then you have to walk 3 spaces to get to the number zero. The distance in the attached picture is along a number line....

A physician orders penicillin 525,000 units q4h for a child who weighs 55 lbs. The recommended dosage is 100,000 250,000 units/kg/day in six divided doses. The pharmacy stocks the 200,000 units/mL concentration. What is the child's weight in kg? What is the safe daily dosage range for this child? Is the ordered dose safe?

Answers

Answer:

a. 24.9476 Kg.

b. The safe daily dosage range is between 2494760 units /day and 6236900 units/day

c. Yes

Step-by-step explanation:

a. Lets see the convertion from lb to Kg:

1 Lb= 0.45359255 lb = 0.453592*55= 24.9476 kg

b. Minimum daily dosage is 100,000 units /kg

For this kid: 100,000 * 24.9476= 2,494,760 units/ dayin 6 dosis; 2494760/6= 415,793.33 units every 4 hours

Maximun daily dosage is 250,000 units /kg

For this kid: 250,000 * 24.9476= 6,236,900 units/ dayin 6 dosis; 6,236,900/6= 1,039,483.33 units every 4 hours

c: Yes, because 525.000 units every 4 hours is between the minimun and maximun dosaje for this kid

There is always a 1 to 1 correspondence between the number guanines (G) and the number of cytosines (C) in a DNA molecule. The same is true of the relationship between adenine (A) and thymine (T). Of course Professor Floop knows this. He analyzed a strand of DNA and determined the amounts of C and G it contained. If the molecule was 22% G, what was the percentage of A, assuming that DNA only contains G, C, A, and T

Answers

Answer:

the strand contains 28% of adenine.

Step-by-step explanation:

We have only four components, and we only know one of them:

[tex]\left[\begin{array}{cc}C&?\\G&22\%\\A&?\\T&?\end{array}\right][/tex]

Cytosine has a relation 1 to 1 with G, therefore the strand must contain the same amount of C as it posses G:

[tex]\left[\begin{array}{cc}C&22\%\\G&22\%\\A&?\\T&?\end{array}\right][/tex]

Therefore:

[tex]A + T = 100\% - (C+G)[/tex]

This is because the strain only contains those 4 components.

since A and T have also a 1 to 1 relation, we can state that A = T in quantity.

So:

[tex]A + A = 100\% - (C+G)[/tex]

[tex] 2A = 100\% - (22\%+22\%)[/tex]

[tex]A = \frac{100\%-44\%}{2}[/tex]

[tex]A = \frac{56%}{2}[/tex]

[tex] A = 28\%[/tex]

Find the quadratic polynomial whose graph goes through the points (-1,8), (0,6), and (2, 26). f(0) = x^2+ x+

Answers

Answer:

4x² + 2x + 6 = 0

Step-by-step explanation:

The polynomial which has highest degree 2 is known as quadratic polynomial. It is of the form:

ax² + bx + c = 0

where, a ≠ 0 and a, b & c are any constant.

We have given three points (-1, 8), (0, 6), and (2, 26)

Putting these value of (x, y) in quadratic equation one by one.

We get, three equations:

8 = a - b + c

6 = c

26 = 4a + 2b + c

Solving these equations, We get,

a = 4, b = 2 and c = 6

Now putting these values of a, b, and c in standard quadratic equation.

We get,

4x² + 2x + 6 = 0

which is required equation.

Are the terms mcg/mL and mg/L equivalent or not equivalent?

Answers

The terms mcg/mL and mg/L are not equivalent.

1. mcg/mL:

"mcg" stands for micrograms, which is a unit of measurement used for very small amounts.

"mL" stands for milliliters, which is a unit of measurement used for volume.

So, mcg/mL represents micrograms per milliliter, which is a measure of concentration.

2. mg/L:

"mg" stands for milligrams, which is a unit of measurement used for larger amounts than micrograms.

"L" stands for liters, which is a unit of measurement used for volume.

Therefore, mg/L represents milligrams per liter, also a measure of concentration.

Since micrograms are smaller than milligrams, mcg/mL is a smaller unit of measurement than mg/L. In other words, 1 mcg/mL is equal to 0.001 mg/L.

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Final answer:

The terms mcg/mL and mg/L are equivalent. This is based on the conversion of these units to grams (g) per liter (L), where both ratios equals to g/L.

Explanation:

The terms mcg/mL and mg/L are indeed equivalent. Here's how we make the conversion: 1 mcg (microgram) is equal to 1x10-6g (grams), and 1 mL (milliliter) is equal to 1x10-3L (liters). Therefore, the ratio of mcg/mL equals to g/L. Now, 1mg (milligram) is equal to 1x10-3g (grams), and if we have 1 L (liter), it is the same 1L. Therefore, the ratio mg/L also equals to g/L. With this we can conclude that mcg/mL is equivalent to mg/L.

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Write an equation for the parabolla

A parabolla with x-intercepts at (-1,0) and (3,0) which passes through the point (1,-8)

Can u show the steps pls

Answers

well, is noteworthy that an x-intercept is when y = 0 or namely is a solution or root of the quadratic, so we know then that the x-intercepts or solutions are at (-1,0) and (3,0), that simply means that

[tex]\bf (\stackrel{x}{-1},\stackrel{y}{0})\qquad (\stackrel{x}{3},\stackrel{y}{0})\qquad \begin{cases} x = -1\\ x+1=0\\ \cline{1-1} x=3\\ x-3=0 \end{cases}~\hfill \implies ~\hfill \stackrel{\textit{equation of the parabola}}{y = a(x+1)(x-3)} \\\\\\ \textit{we also know that } \begin{cases} x = 1\\ y = -8 \end{cases}\implies \underline{-8}=a(\underline{1}+1)(\underline{1}-3)[/tex]

[tex]\bf -8=a(2)(-2)\implies -8=-4a\implies \cfrac{-8}{-4}=a\implies \boxed{2=a} \\\\[-0.35em] ~\dotfill\\\\ y=2(x+1)(x-3)\implies y=2(\stackrel{\mathbb{FOIL}}{x^2-2x-3})\implies y=2x^2-4x-6[/tex]

Construct a truth table for proposition (¬p)\rightarrowq

Answers

Answer:

[tex]\left[\begin{array}{ccc}(-p)&--->&q\\f&t&t\\f&t&t\\t&t&f\\t&f&f\end{array}\right][/tex]

Step-by-step explanation:

First, we find all the possibilities for p and q in a table:

p  q

t    t

t    f

f    t

f    f

then -p:

-p  q

f    t

f    f

t    t

t    f

and we apply the operator --> (rightarrow), that is only f (false) y if the first one is t (true) and the second one is f (false)

-p    --->    q

f       t       t

f       t       f

t       t       t

t       f       f

Some one do this pls

Answers

Answer:

  5.  B

  6.  J

Step-by-step explanation:

5. The lower left point on the graph is (1, 5). The only answer choice containing this point is choice B.

__

6. The "range" is the list of y-values. This is also the list of second values in the ordered pairs of the answer to question 5. They are ...

 {5, 6, 10, 15} . . . . matches choice J

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