suppose a and b are n × n, b is invertible, and ab is invertible. show that a is invertible. [hint: let c = ab, and solve the equation for a.]

Answers

Answer 1

If a and b are n × n, b is invertible, and ab is invertible, then a is also invertible.


How to show that a is invertible?

To show that a is invertible, we need to find an inverse matrix [tex]A^-^1[/tex]such that A[tex]A^-^1 = A^-^1A[/tex] = I (the identity matrix).

Let's begin by using the hint provided and letting c = ab. We know that b is invertible, so we can multiply both sides of c = ab by b^-1 (the inverse of b) to get:

[tex]c(b^-^1) = ab(b^-^1)c(b^-^1) = a(bb^-^1)c(b^-^1) = aIc(b^-^1) = a[/tex]

Now we substitute c = ab back into the equation to get:

[tex]ab(b^-^1) = a[/tex]

Next, we can use the fact that ab is invertible to say that there exists some inverse matrix[tex](ab)^-^1[/tex] such that [tex](ab)(ab)^-^1 = (ab)^-^1(ab)[/tex] = I. Multiplying both sides of this equation by [tex]b^-^1[/tex], we get:

[tex]a(bb^-^1)(ab)^-^1 = (ab)^-^1(bb^-^1)a^-^1[/tex]
[tex]aI(ab)^-^1 = (ab)^-^1I[/tex]
[tex]a(ab)^-^1 = (ab)^-^1[/tex]

So we have shown that a multiplied by the inverse of ab is equal to the inverse of ab. This means that a must also be invertible, since the inverse of ab exists and we can simply multiply it by a to get the inverse of a. Therefore, we have proven that if a and b are n × n, b is invertible, and ab is invertible, then a is also invertible.

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Related Questions

in boundary value analysis both the valid inputs and invalid inputs are being tested to verify the issues. T/F

Answers

Boundary value analysis is a testing technique used to identify defects or issues at the boundaries or limits of input values. True, in boundary value analysis both valid and invalid inputs are tested to verify potential issues.

Boundary value analysis is a testing technique used to identify defects or issues at the boundaries or limits of input values. The main idea is to test inputs that are just above, just below, and exactly at the specified boundaries or limits. This helps in uncovering potential issues that may arise due to boundary conditions.

Valid inputs are those that fall within the acceptable range of values, while invalid inputs are those that fall outside the acceptable range of values. Both valid and invalid inputs are tested during boundary value analysis to ensure thorough testing of the system under test. By testing valid inputs, we can verify if the system handles inputs within the acceptable range correctly. By testing invalid inputs, we can identify any issues or defects that may arise when inputs fall outside the acceptable range.

Therefore, in boundary value analysis, both valid and invalid inputs are tested to verify potential issues or defects in the system

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(56x^2-60x+16)
Divided by
28x-16

Answers

Answer:

= 2x - 1

Step-by-step Explanation:

We can use polynomial long division to divide (56x^2-60x+16) by (28x-16).



2x - 1
-------------------
28x - 16 | 56x^2 - 60x + 16
56x^2 - 32x
------------
-28x + 16
-28x + 16
---------
0

Therefore, the quotient is 2x - 1 and the remainder is 0. So we have:

(56x^2-60x+16) / (28x-16) = 2x - 1

Answer: the quotient is 2x - 1 and the remainder is 0. So we can write:

(56x^2-60x+16) ÷ (28x-16) = 2x - 1.

Step-by-step explanation:

2x - 1

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

28x - 16 | 56x^2 - 60x + 16

56x^2 - 32x

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

-28x + 16

-28x + 16

----------

0

At the same rate, how long would it take him to drive 335 miles?

Answers

It would take Deshaun 5 hours to drive 335 miles at the same rate.

What is speed?

The SI unit of speed is m/s, and speed is defined as the ratio of distance to time. It is the shift in an object's location with regard to time.

We can use the formula:

rate = distance / time

to solve the problem. The rate is constant, so we can use it to find the time for a different distance.

First, we find Deshaun's rate:

rate = distance / time = 469 miles / 7 hours = 67 miles per hour

Now we can use this rate to find the time it would take to drive 335 miles:

time = distance / rate = 335 miles / 67 miles per hour

time = 5 hours

Therefore, it would take Deshaun 5 hours to drive 335 miles at the same rate.

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The complete question is:

Deshaun drove 469 miles in 7 hours. At the same rate, how long would it take him to drive 335 miles?

The probability of a sunny day in July in the state of Virginia is 0.75. What is the probability of at least one cloudy day in a five-day span (assuming the days are independent)?

Answers

The probability of at least one cloudy day in a five-day span is 0.7627 or approximately 0.76.

How to find the probability of at least one cloudy day in a five-day span?

The probability of a sunny day in Virginia in July is 0.75, which means the probability of a cloudy day is 1 - 0.75 = 0.25.

Assuming the days are independent, the probability of at least one cloudy day in a five-day span can be calculated using the complement rule:

P(at least one cloudy day) = 1 - P(no cloudy days)

The probability of no cloudy days in a five-day span is the probability that all five days are sunny, which is [tex](0.75)^5[/tex] = 0.2373.

Therefore, the probability of at least one cloudy day in a five-day span is:

P(at least one cloudy day) = 1 - P(no cloudy days) = 1 - 0.2373 = 0.7627

So the probability of at least one cloudy day in a five-day span is 0.7627 or approximately 0.76.

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Solve the following differential equations using the method of undetermined coefficients.

a) y''-5y'+4y=8ex​
b) y''-y'+y=2sin3x

Determine the form of a particular solution. a) y(4)+y'''=1-x2e-x​ b) y'''-4y''+4y'=5x2-6x+4x2e2x+3e5x

Answers

a) The general solution is y(x) = y_c(x) + y_p(x) = c1e^x + c2e^(4x) + 8ex.

b) The general solution is y(x) = y_c(x) + y_p(x) = c1e^(x/2)cos((√3/2)x) + c2e^(x/2)sin((√3/2)x) - (1/4)sin(3x).

For the differential equation y'' - 5y' + 4y = 8ex, the characteristic equation is r^2 - 5r + 4 = 0, which has roots r1 = 1 and r2 = 4. Thus, the complementary function is y_c(x) = c1e^x + c2e^(4x).

To find the particular solution, we guess a solution of the form y_p(x) = Ae^x. Then, y_p''(x) - 5y_p'(x) + 4y_p(x) = Ae^x - 5Ae^x + 4Ae^x = Ae^x. We need this to equal 8ex, so we set A = 8, and the particular solution is y_p(x) = 8ex.

Thus, the general solution is y(x) = y_c(x) + y_p(x) = c1e^x + c2e^(4x) + 8ex.

b) For the differential equation y'' - y' + y = 2sin(3x), the characteristic equation is r^2 - r + 1 = 0, which has roots r1,2 = (1 ± i√3)/2. Thus, the complementary function is y_c(x) = c1e^(x/2)cos((√3/2)x) + c2e^(x/2)sin((√3/2)x).

To find the particular solution, we guess a solution of the form y_p(x) = A sin(3x) + B cos(3x). Then, y_p''(x) - y_p'(x) + y_p(x) = -9A sin(3x) - 9B cos(3x) - 3A cos(3x) + 3B sin(3x) + A sin(3x) + B cos(3x) = -8A sin(3x) - 6B cos(3x). We need this to equal 2sin(3x), so we set A = -1/4 and B = 0, and the particular solution is y_p(x) = (-1/4)sin(3x).

Thus, the general solution is y(x) = y_c(x) + y_p(x) = c1e^(x/2)cos((√3/2)x) + c2e^(x/2)sin((√3/2)x) - (1/4)sin(3x).

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ratio of 3 boys and 4 girls there are now 12 boys

Answers

Answer:

There are 16 girls.

Step-by-step explanation:

3 : 4

12 : x

Now if we cross multiply:

3(x) = 12(4)

3x = 48

x = 16

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7. A physician assistant applies gloves prior to examining each patient. She sees an
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average of 37 patients each day. How many boxes of gloves will she need over the
span of 3 days if there are 100 gloves in each box?
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8. A medical sales rep had the goal of selling 500 devices in the month of November.
He sold 17 devices on average each day to various medical offices and clinics. By
how many devices did this medical sales rep exceed to fall short of his November
goal?
9. There are 56 phalange bones in the body. 14 phalange bones are in each hand. How
many phalange bones are in each foot?
10. Frank needs to consume no more than 56 grams of fat each day to maintain his
current weight. Frank consumed 1 KFC chicken pot pie for lunch that contained 41
grams of fat. How many fat grams are left to consume this day?
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11. The rec center purchases premade smoothies in cases of 50. If the rec center sells
an average of 12 smoothies per day, how many smoothies will be left in stock after
4 days from one case?
12. Ashton drank a 24 oz bottle of water throughout the day at school. How many
ounces should he consume the rest of the day if the goal is to drink the
recommended 64 ounces of water per day?
13. Kathy set a goal to walk at least 10 miles per week. She walks with a friend 3
times each week and averages 2.5 miles per walk. How many more miles will she
need to walk to meet her goal for the week?

Answers

On quantities:

3 boxes.

10 devices.

28 phalange bones.

15 grams of fat.

2 smoothies left.

1256 oz of water.

2.5 miles.

How to calculate quantity?

7. The physician assistant sees an average of 37 x 3 = 111 patients over 3 days.

Since each patient requires 2 gloves, the total number of gloves needed is 111 x 2 = 222 gloves.

Since there are 100 gloves in each box, the number of boxes needed is 222/100 = 2.22, which rounds up to 3 boxes.

8. The medical sales rep sells 17 devices per day on average. To sell 500 devices in November, the sales rep needs to sell 500/30 = 16.67 devices per day on average.

The sales rep exceeds the goal by 17 - 16.67 = 0.33 devices per day on average.

Therefore, the sales rep exceeds the goal by 0.33 x 30 = 10 devices.

9. There are 56 - (14 x 2) = 28 phalange bones in each foot.

10. Frank consumed 41 grams of fat for lunch, so he has 56 - 41 = 15 grams of fat left to consume.

11. The rec center sells an average of 12 smoothies per day, so in 4 days, it will sell 12 x 4 = 48 smoothies.

Since there are 50 smoothies in each case, there will be 50 - 48 = 2 smoothies left in stock after 4 days.

12. Ashton drank 24 oz of water, so he needs to drink an additional 64 - 24 = 40 oz of water.

Since 1 oz = 0.03125 cups, Ashton needs to drink 40/0.03125 = 1280 cups of water.

Therefore, Ashton needs to drink 1280 - 24 = 1256 oz of water for the rest of the day.

13. Kathy walks 3 times a week for a total of 3 x 2.5 = 7.5 miles.

To meet her goal of 10 miles per week, Kathy needs to walk an additional 10 - 7.5 = 2.5 miles.

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Kendra put up 50 ft of fencing between her yard and her neighbors. If the fencing costs $13 a foot, she paid $ for the fencing.

Answers

Answer: $650

Step by step solution:

1) 50 x 13 = 650

answer: $650

To find how much Kendra paid per foot, we can divide the total cost of the fencing by the length of the fencing.

The length of the fencing is given as 50 feet.

The total cost of the fencing can be found by multiplying the cost per foot by the length of the fencing:

Total cost = Cost per foot x Length of fencing Total cost = $13/ft x 50 ft Total cost = $650

Therefore, Kendra paid a total of $650 for 50 feet of fencing. To find how much she paid per foot, we can divide the total cost by the length of the fencing:

Cost per foot = Total cost / Length of fencing Cost per foot = $650 / 50 ft Cost per foot = $13/ft

So Kendra paid $13 per foot of fencing.

For time t ≥ 0, the acceleration of an object moving in a straight line is given by a (t) = ln(3 +t^4). What is the net change in velocity from time t = 1 to time t = 5?

Answers

The net change in velocity from time t=1 to time t=5 is approximately 34.65 units.

To find the net change in velocity from time t=1 to time t=5, we need to integrate the acceleration function a(t) = ln(3 + t⁴) with respect to time between t=1 and t=5.

∫(a(t) dt) from 1 to 5 = ∫(ln(3 + t⁴) dt) from 1 to 5

Using the substitution u = 3 + t⁴ and du/dt = 4t³, we get:

∫(ln(3 + t⁴) dt) = (1/4)∫(ln(u) du)

= (1/4) [u × ln(u) - u] from 3 + 1⁴ to 3 + 5⁴

= (1/4) [(3+5⁴)×ln(3+5⁴) - (3+1⁴)×ln(3+1⁴) - (3+5⁴) + (3+1⁴)]

≈ 34.65

Therefore, the net change in velocity from time t=1 to time t=5 is approximately 34.65 units.

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If the inputs of a J-K flip-flop are J= 1 and K = 1 while the outputs are Q = 0 and Q= 1, what will the outputs be after the next clock pulse occurs? A) Q=0,Q=0 B) Q=1,Q=1 C) Q=1,Q=0 D) Q=0,Q= = 1 An eight-line multiplexer must have A) four data inputs and three select inputs. C) eight data inputs and four select inputs. B) eight data inputs and two select inputs. D) eight data inputs and three select inputs.

Answers

If the inputs of a J-K flip-flop are J= 1 and K = 1 while the outputs are Q = 0 and Q= 1, the outputs after the next clock pulse occurs are C) Q=1, Q=0. An eight-line multiplexer must have D) eight data inputs and three select inputs.

For the first question, with the J-K flip-flop:
Given inputs J = 1 and K = 1, and outputs Q = 0 and Q' = 1. After the next clock pulse occurs, the outputs will be:
A) Q = 0, Q' = 0
B) Q = 1, Q' = 1
C) Q = 1, Q' = 0
D) Q = 0, Q' = 1
Answer: Since the J-K flip-flop is in toggle mode when J = 1 and K = 1, the outputs will toggle. Therefore, the correct answer is C) Q = 1, Q' = 0.
For the second question, regarding an eight-line multiplexer:
A) four data inputs and three select inputs.
B) eight data inputs and two select inputs.
C) eight data inputs and four select inputs.
D) eight data inputs and three select inputs.
Answer: An eight-line multiplexer requires three select inputs to choose from eight data inputs ([tex]2^3[/tex] = 8). Therefore, the correct answer is D) eight data inputs and three select inputs.

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In one flip of 10 unbiased coins, what is the probability of getting a result as extreme or more extreme than 8 heads?
a.0547
b.1094
c. 2246
d.Impossible to determine

Answers

The probability of getting a result as extreme or more extreme than 8 heads is 0.0547, which corresponds to answer choice (a).

The probability of getting a result as extreme or more extreme than 8 heads in one flip of 10 unbiased coins can be found using the binomial probability formula. We need to calculate the probability of getting exactly 8 heads, 9 heads, and 10 heads, then sum them up.

The binomial probability formula is: P(X=k) = C(n, k) × p^k × (1-p)^(n-k), where C(n, k) represents the number of combinations, n is the number of trials (in this case, 10 coin flips), k is the number of successful outcomes (heads), and p is the probability of success (0.5 for unbiased coins).

P(8 heads) = C(10, 8) × 0.5⁸ × 0.5² = 45 × 0.0039 × 0.25 = 0.0439
P(9 heads) = C(10, 9) × 0.5⁹ × 0.5¹ = 10 × 0.00195 × 0.5 = 0.0098
P(10 heads) = C(10, 10) × 0.5¹⁰ × 0.5⁰ = 1 × 0.00098 × 1 = 0.00098

Now, add these probabilities together: 0.0439 + 0.0098 + 0.00098 = 0.0547.

Therefore, the probability of getting a result as extreme or more extreme than 8 heads is 0.0547, which corresponds to answer choice (a).

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An artist is making a square stained glass window in which a green glass circle is surrounded by blue glass. The side length of the window is shown, and the area of the green piece is 64PIr^2. What is the area of the blue glass?

Answers

The area of the blue glass is 400x² - 6400πx².

We have,

The area of the square window is:

A = (20x)² = 400x²

The area of the green glass circle is given as:

A_g = 64πr²

However, we need to find the radius of the circle in terms of x.

Since the circle is inscribed in the square, its diameter is equal to the side length of the square:

d = 20x

r = d/2 = 10x

Substituting this value for r in the expression for A_g:

A_g = 64π(10x)² = 6400πx²

The area of the blue glass is the difference between the area of the square and the area of the green glass circle:

A_b = A - A_g = 400x² - 6400πx²

Thus,

The area of the blue glass is 400x² - 6400πx².

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The area of the blue glass is 400x² - 6400πx².

We have,

The area of the square window is:

A = (20x)² = 400x²

The area of the green glass circle is given as:

A_g = 64πr²

However, we need to find the radius of the circle in terms of x.

Since the circle is inscribed in the square, its diameter is equal to the side length of the square:

d = 20x

r = d/2 = 10x

Substituting this value for r in the expression for A_g:

A_g = 64π(10x)² = 6400πx²

The area of the blue glass is the difference between the area of the square and the area of the green glass circle:

A_b = A - A_g = 400x² - 6400πx²

Thus,

The area of the blue glass is 400x² - 6400πx².

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write cos(sin^-1x-tan^-1y) in terms of x and y

Answers

cos(sin⁻¹ˣ-tan^-1y) can be written as: x/√(1+y²) + √(1-x²)/√(1+y²). This can be answered by the concept of Trigonometry.

We can use the trigonometric identity cos(a-b) = cos(a)cos(b) + sin(a)sin(b) to write cos(sin⁻¹ˣ-tan^-1y) in terms of x and y.

Let a = sin⁻¹ˣ and b = tan^-1y, then we have:

cos(sin⁻¹ˣ-tan^-1y) = cos(a-b)

= cos(a)cos(b) + sin(a)sin(b)

= (√(1-x²))(1/√(1+y²)) + x/√(1+y²)

= x/√(1+y²) + √(1-x²)/√(1+y²)

Therefore, cos(sin⁻¹ˣ-tan^-1y) can be written as:

x/√(1+y²) + √(1-x²)/√(1+y²)

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what is the least common multiple of 24 and 32?
i need an answer asap ​

Answers

96

Explanation:

Write the prime factorization of both the numbers.

24=2×2×2×3

32=2×2×2×2×2

The LCM of 24 and 32 is 96. To find the LCM (least common multiple) of 24 and 32, we need to find the multiples of 24 and 32 (multiples of 24 = 24, 48, 72, 96; multiples of 32 = 32, 64, 96, 128) and choose the smallest multiple that is exactly divisible by 24 and 32

find the first quadrant area bounded by the curve y 2 = 5 − x and both coordinate axes.

Answers

The area of the first quadrant bounded by the curve and both coordinate axes is 2/3 ([tex]5^{(3/2)}[/tex] - 5).

The given curve is y² = 5 - x, which is a parabola opening towards the left with a vertex at (5,0).

To find the area of the first quadrant bounded by the curve and both coordinate axes, we need to integrate the curve with respect to x over the range [0,5].

Since the curve is given in terms of y², we can rewrite it as y = ±√(5-x). However, we only need the positive root for the first quadrant, so we have y = √(5-x).

Thus, the area can be calculated as:

A = ∫[0,5] y dx

= ∫[0,5] √(5-x) dx

= 2/3 ([tex]5^{(3/2)}[/tex] - 5)

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the alpha level for a hypothesis test is value that defines the concept of "" ."" the critical region consists of the that are to occur (as defined by the ) if the hypothesis is true.

Answers

The alpha level for a hypothesis test is the significance level that defines the threshold for rejecting the null hypothesis.The critical region consists of the values of the test statistic that would lead to the rejection of the null hypothesis if observed, as defined by the chosen alpha level.

What is the significance of the alpha level in hypothesis testing and how does it relate to the critical region?

The alpha level for a hypothesis test is a value that defines the concept of "significance level" or "level of significance".

The significance level, denoted as α, represents the threshold at which the null hypothesis is rejected in favor of the alternative hypothesis. It is a predetermined value chosen by the researcher to determine the level of confidence required to reject the null hypothesis.

The critical region, also known as the rejection region, consists of the extreme or unlikely values of the test statistic that would lead to the rejection of the null hypothesis.

These values are determined based on the chosen alpha level. If the calculated test statistic falls within the critical region, the null hypothesis is rejected in favor of the alternative hypothesis.

The critical region is defined by the alpha level, and it represents the probability of observing extreme test statistics under the assumption that the null hypothesis is true.

In other words, it defines the values of the test statistic that would be considered statistically significant, and that would lead to the rejection of the null hypothesis if observed.

The specific values that define the critical region are determined by the nature of the hypothesis test and the type of test being conducted, such as one-tailed or two-tailed test.

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find the area of the region that is bounded by the curve r=2sin(θ)−−−−−−√ and lies in the sector 0≤θ≤π.

Answers

The area of the region bounded by the curve r = 2sin(θ) in the sector 0≤θ≤π is π/2 square units.

The curve given by the polar equation r = 2sin(θ) is a sinusoidal spiral that starts at the origin, goes out to a maximum distance of 2 units, and then spirals back into the origin as θ increases from 0 to 2π. The sector 0≤θ≤π is half of this spiral, so we can find its area by integrating the area element dA = 1/2 r^2 dθ over this sector

A = ∫[0,π] 1/2 (2sin(θ))^2 dθ

Simplifying the integrand and applying the half-angle identity for sin^2(θ), we get

A = ∫[0,π] sin^2(θ) dθ

= ∫[0,π] (1 - cos^2(θ)) dθ

Integrating term by term, we get

A = [θ - 1/2 sin(2θ)]|[0,π]

= π/2 square units.

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0.48 points] details scalc9 15.3.039. my notes ask your teacher evaluate the iterated integral by converting to polar coordinates. 6 0 √36 − x 2 0 e−x2 − y2 dy dx

Answers

The iterated integral by converting to polar coordinates is:

-1/2([tex]e^{(-36) }[/tex] - 1)

What is iterated integral?

An iterated integral is a mathematical concept used to calculate the area, volume, or mass of an object. It is the process of evaluating a double or triple integral by integrating one variable at a time. In the case of a double integral, this means integrating first with respect to one variable and then integrating the result with respect to the other variable. In the case of a triple integral, this means integrating first with respect to one variable, then the second, and finally the third.

According to the given information

For the given problem, we have the iterated integral:

∫₀⁶ ∫₀√(36-x²) [tex]e^{(x^{2}-y^{2} ) }[/tex] dy dx

To convert to polar coordinates, we first need to draw the region of integration. The region is a quarter circle centered at the origin with a radius of 6.

Next, we determine the bounds of integration. Since the region is a quarter circle, we have 0 ≤ θ ≤ π/2 and 0 ≤ r ≤ 6.

To express the integrand in terms of r and θ, we use the substitution x = r cos(θ) and y = r sin(θ). This gives us:

[tex]e^{(-x^{2}-y^{2} ) }[/tex]= [tex]e^{(-r^{2}) }[/tex]

Substituting these into the original integral, we get:

∫₀⁶ ∫₀π/2 [tex]e^{(-r^{2}) }[/tex] r dr dθ

This is the double integral in polar coordinates. We can now evaluate it using the limits of integration and the integrand expressed in terms of r and θ. The integration gives:

-1/2([tex]e^{(-36)}[/tex]- 1)

So the final answer is -1/2([tex]e^{(-36)}[/tex] - 1).

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There are 28 students in a class.
13 of the students are boys.
Two students from the class are chosen at random.
a) If the first person chosen is a boy, what is the probability that
the second person chosen is also a boy?
Give your answer as a fraction.
b) What is the probability that both students chosen are girls?
Give your answer as a fraction.
(1)
(1)

Answers

a)  If the first person chosen is a boy, what is the probability that

the second person chosen is also a boy is: 12/27

b) The probability that both students chosen are girls is: 5/18

How to find the probability of selection?

The parameters given are:

There are 28 students in a class

13 of the students are boys

According to the question we have

When first chosen a boy , then the rest is

28 - 1 = 27

Then the rest boys are 12

From 27, has 12 boys

The probability that the second person also is a boy = 12/27

b) There are:

28 - 13 = 15 girls

Probability that first is a girl = 15/28

Probability that second is a girl = 14/27

Thus:

P(both are girls) = (15/28) * (14/27) = 5/18

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Let Z be the set of all integers and let
A0 = {n ∈ Z | n = 4k, for some integer k},
A1 ={n ∈ Z | n = 4k + 1, for some integer k},
A2 = {n ∈ Z | n = 4k + 2, for some integer k}, and
A3 = {n ∈ Z | n = 4k + 3, for some integer k}.
Is {A0, A1, A2, A3} a partition of Z? Explain your answer.

Answers

Yes, {A0, A1, A2, A3} it is a partition of the set Z.

What is a partition of a set?

Yes, {A0, A1, A2, A3} is a partition of the set Z, which consists of all integers. To explain why this is a partition, let's consider the definition of a partition and examine each subset:

A partition of a set is a collection of non-empty, disjoint subsets that together contain all the elements of the original set. In this case, we need to show that A0, A1, A2, and A3 are non-empty, disjoint, and together contain all integers.

1. Non-empty: Each subset Ai (i=0,1,2,3) contains integers based on the value of k. For example, A0 contains all multiples of 4, A1 contains all numbers 1 more than a multiple of 4, and so on. Since there are integers that fit these criteria, each subset is non-empty.

2. Disjoint: The subsets are disjoint because each integer n can only belong to one subset. If n = 4k, it cannot also be 4k + 1, 4k + 2, or 4k + 3 for the same integer k. Similarly, if n = 4k + 1, it cannot also be 4k, 4k + 2, or 4k + 3, and so on for A2 and A3.

3. Contains all integers: Any integer n can be expressed as 4k, 4k + 1, 4k + 2, or 4k + 3 for some integer k. This covers all possible integers in Z. For example, if n is divisible by 4, it belongs to A0; if it has a remainder of 1 when divided by 4, it belongs to A1; and so on.

Therefore, since {A0, A1, A2, A3} satisfies all the conditions for a partition, it is a partition of the set Z.

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the radius of a circle is increasing at a rate of centimeters per second. part 1: write an equation to compute the area A of the circle using the radius r . use pi for
A = ______ cm.

Answers

The equation to compute the area A of the circle is: [tex]A = π(r^2 - r0^2) + A0[/tex] where r0 is the initial radius and A0 is the initial area.

The equation to compute the area A of a circle with radius r is [tex]A = πr^2[/tex].

Using this equation and the given information that the radius is increasing at a rate of centimeters per second, we can write:

[tex]\frac{dA}dt} = 2rπ \frac{dr}{dt}[/tex]

where dA/dt represents the rate of change of area with respect to time, and [tex]\frac{dr}{dt}[/tex] represents the rate of change of radius with respect to time.

Part 1:

If we want to find the area of the circle at a specific time t, we can integrate both sides of the equation with respect to time:

[tex]\int\limits dA= \int\limits 2πr \frac{dr}{dt}  \, dt[/tex]

Integrating both sides gives:

[tex]A = πr^2 + C[/tex]

where C is the constant of integration. Since we are given the initial radius, we can use it to find the value of C:

When t = 0, r = r0

[tex]A = πr0^2 + C[/tex]

Therefore, [tex]C = A - πr0^2[/tex]

Substituting this value of C back into the equation gives:

[tex]A = πr^2 + A - πr0^2[/tex]

Simplifying gives:


[tex]A =π(r^2 - r0^2) + A0[/tex]

where A0 is the initial area of the circle.

Therefore, the equation to compute the area A of the circle is:

[tex]A = π(r^2 - r0^2) + A0[/tex]

where r0 is the initial radius and A0 is the initial area.

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In an independent-measures t test if the sample variances are very large, it is possible to obtain a significant difference between treatments even if the actual mean difference is very small.
Answer
a. False
b. True

Answers

b. True

In an independent-measures t-test, if the sample variances are very large, it is possible to obtain a significant difference between treatments even if the actual mean difference is very small. This is because a larger variance can lead to a larger t-value, which can be considered statistically significant.

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I want to see if there is an association between hours of sleep and calories consumed per day. What statistical analysis would I use?
A. Chi Square
B. Pearson's R
C. Spearman's rho
D. Students T-test

Answers

To determine if there is an association between hours of sleep and calories consumed per day,

you should use option B: Pearson's R. Pearson's R, also known as Pearson's correlation coefficient, measures the strength and direction of the linear relationship between two continuous variables, in this case, sleep and calories.

Pearson's correlation coefficient:

The Pearson correlation coefficient (r) is the most common way of measuring linear correlation. It is a number between –1 and 1 that measures the strength and direction of the relationship between two variables. When one variable changes, the other variable changes in the same direction.

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To determine if there is an association between hours of sleep and calories consumed per day,

you should use option B: Pearson's R. Pearson's R, also known as Pearson's correlation coefficient, measures the strength and direction of the linear relationship between two continuous variables, in this case, sleep and calories.

Pearson's correlation coefficient:

The Pearson correlation coefficient (r) is the most common way of measuring linear correlation. It is a number between –1 and 1 that measures the strength and direction of the relationship between two variables. When one variable changes, the other variable changes in the same direction.

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The area below the price and above the supply curve measures the producer surplus in a market. a. TRUE b. FALSE.

Answers

The statement "The area below the price and above the supply curve measures the producer surplus in a market" is a. TRUE.

Producer surplus is represented by this area, as it shows the difference between the market price and the minimum price a producer is willing to accept for a good or service.

The area below the price and above the supply curve represents the amount that producers are willing to sell their goods for (supply curve) and the price that they actually receive (market price).

The difference between these two amounts is the producer surplus, which is the measure of the benefit that producers receive from participating in a market.

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3. Simplify:
(1-2)(¹-3) (1-4)-(1-99) (1-700)

Answers

We can simplify this expression by using the order of operations (PEMDAS) and distributing the negative sign:

(1-2)(¹-3) (1-4)-(1-99) (1-700) = (-1)(-2) (-2)-(1-99) (-699)

Simplifying further, we have:

(-1)(-2) = 2
(-2)-(1-99) = -2 - (-98) = 96
(-699) = -699

Putting it all together, we get:

2*96 - (-699) = 192 + 699 = 891

Therefore, the simplified expression is 891.

. Let A and B be similar matrices and let λ be any scalar. Show that
(a) A − λI and B − λI are similar.
(b) det(A − λI) = det(B − λI).

Answers

First, let's recall that two matrices A and B are considered similar if there exists an invertible matrix P such that A = PBP⁻¹.

Now, let's use this definition to prove both parts of the question:
(a) We want to show that A − λI and B − λI are similar. To do this, we need to find an invertible matrix P such that (A − λI) = P(B − λI)P⁻¹.

Let's start by manipulating the equation A = PBP⁻¹ to get A − λI = P(B − λI)P⁻¹.
Now, let's substitute this into the equation we want to prove:
A − λI = P(B − λI)P⁻¹

We want to show that this is equivalent to:
A − λI = Q(B − λI)Q⁻¹
for some invertible matrix Q.

To do this, let's try to manipulate the equation we have into the form we want:

A − λI = P(B − λI)P⁻¹
A − λI = PBP⁻¹ − λP(P⁻¹)
A − λI = PBP⁻¹ − λI
A = PB(P⁻¹) + λI

Now, let's try to get this into the form we want:

A = Q(B − λI)Q⁻¹
A = QBQ⁻¹ − λQ(Q⁻¹)
A = QBQ⁻¹ − λI
A = QB(Q⁻¹) + λI

Comparing the two equations, we see that if we let Q = P, we get the equation we want:

A − λI = PBP⁻¹ − λI
A − λI = QBQ⁻¹ − λI
Thus, A − λI and B − λI are similar.

(b) We want to show that det(A − λI) = det(B − λI).
From part (a), we know that A − λI and B − λI are similar, so there exists an invertible matrix P such that A − λI = P(B − λI)P⁻¹.
Now, let's take the determinant of both sides:
det(A − λI) = det(P(B − λI)P⁻¹)
det(A − λI) = det(P)det(B − λI)det(P⁻¹)
det(A − λI) = det(B − λI)
since det(P) and det(P⁻¹) cancel out.

Therefore, det(A − λI) = det(B − λI).

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find the global extreme values of f(x, y) = x^2 − xy +y^2 on the closed triangular region in the first quadrant bounded by the lines x = 4, y = 0, and y = x.

Answers

The global maximum value of f(x, y) on the closed triangular region occurs at either (4, 0) or (0, 4), both of which have a value of 16.

The global minimum value of f(x, y) occurs at the critical point (0, 0), with a value of 0

How to find the global maximum and minimum value of [tex]f(x,y)[/tex]?

To find the Optimization of multivariable functions i.e, global extreme values of [tex]f(x, y) = x^2 - xy + y^2[/tex] on the closed triangular region in the first quadrant bounded by the lines x = 4, y = 0, and y = x,

We need to first find the critical points of the function in the interior of the region and evaluate the function at these points, and then evaluate the function at the boundary points of the region.

To find the critical points of the function in the interior of the region, we need to solve the system of partial derivatives:

[tex]df/dx = 2x - y = 0\\f/dy = -x + 2y = 0[/tex]

Solving this system of equations, we get the critical point (x, y) = (0, 0).

To check whether this point is a maximum or a minimum, we need to evaluate the second partial derivatives of f:

[tex]d^2f/dx^2 = 2\\d^2f/dy^2 = 2\\d^2f/dxdy = -1[/tex]

The determinant of the Hessian matrix is:

[tex]d^2f/dx^2 \times d^2f/dy^2 - (d^2f/dxdy)^2 = 4 - 1 = 3[/tex]

Since this determinant is positive and [tex]d^2f/dx^2 = d^2f/dy^2 = 2[/tex] are both positive, the critical point (0, 0) is a local minimum.

Next, we need to evaluate the function at the boundary points of the region. These are:

(4, 0): f(4, 0) = 16

(0, 0): f(0, 0) = 0

(0, 4): f(0, 4) = 16

(y, y) for 0 ≤ y ≤ 4: [tex]f(y, y) = 2y^2 - y^2 = y^2[/tex]

Therefore, the global maximum value of f(x, y) on the closed triangular region occurs at either (4, 0) or (0, 4), both of which have a value of 16.

The global minimum value of f(x, y) occurs at the critical point (0, 0), with a value of 0.

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e is bounded by the parabolic cylinder z − 1 2 y 2 and the planes x 1 z − 1, x − 0, and z − 0; sx, y, zd − 4

Answers

The volume of the region that bounds e is 15/2.

To visualize the region bounded by the parabolic cylinder, planes, and the plane z = 4, we can plot the surfaces using a 3D graphing software or by hand.

The parabolic cylinder z - 1/2 y^2 is a cylinder that opens upwards along the z-axis and its cross-sections perpendicular to the z-axis are parabolas. The planes x = 0 and z = 0 bound the cylinder on the left and at the bottom, respectively. The plane x = 1 bounds the cylinder on the right, and the plane z = 4 bounds it from above.

The intersection of the parabolic cylinder and the plane z = 4 is a parabolic curve in the plane z = 4. The intersection of the parabolic cylinder and the plane x = 1 is a straight line segment that runs along the y-axis from y = -2 to y = 2. The intersection of the parabolic cylinder and the plane z = 0 is the x-y plane, which contains the bottom of the cylinder.

To find the region that bounds e, we need to find the points where the parabolic cylinder intersects the planes x = 0, x = 1, and z = 1, and then determine the region that lies between these curves.

The intersection of the parabolic cylinder and the plane x = 0 is the y-axis. Therefore, the left boundary of the region is y = -2 and the right boundary is y = 2.

The intersection of the parabolic cylinder and the plane x = 1 is a line segment along the y-axis from y = -2 to y = 2. Therefore, the region is bounded on the left by the y-axis and on the right by the line segment x = 1, y = z^2/2 + 1/2.

The intersection of the parabolic cylinder and the plane z = 1 is a parabolic curve in the plane z = 1. To find the equation of this curve, we substitute z = 1 into the equation of the parabolic cylinder:

1 - 1/2 y^2 = x

Solving for y^2, we get:

y^2 = 2 - 2x

Therefore, the equation of the parabolic curve in the plane z = 1 is:

y = ±sqrt(2 - 2x)

The region bounded by the parabolic cylinder, planes, and the plane z = 4 is

therefore the region is given by:

0 ≤ x ≤ 1
-y/2 + 1/2 ≤ z ≤ 4
-y ≤ x^2/2 - 1/2

To visualize this region in 3D, we can plot the parabolic cylinder and the planes x = 0, x = 1, and z = 1 and shade the region between them. Then, we can extend this region upwards to the plane z = 4 to obtain the full region that bounds e.

To find the volume of this region, we can integrate the function 1 over this region with respect to x, y, and z:

∫∫∫_R 1 dV

where R is the region defined by the inequalities above. However, this triple integral is difficult to evaluate directly, so we can use the fact that the region is symmetric about the y-axis to simplify the integral by integrating first with respect to y and then with respect to x and z:

V = 2∫∫∫_R 1 dV

where the factor of 2 accounts for the symmetry of the region. Integrating with respect to y first, we get:

V = 2∫_{-2}^{2} ∫_{y^2/2 - 1/2}^{1/2} ∫_{-y/2 + 1/2}^{4} 1 dz dx dy

Evaluating this integral, we get:

V = 15/2

Therefore, the volume of the region that bounds e is 15/2.

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Find the dependent value
for the graph
y = 20 - 2x
when the independent value is 5.
y = [?]

Answers

Answer:

To find the dependent value for the graph y = 20 - 2x when the independent value is 5, we substitute x = 5 into the equation and solve for y.

y = 20 - 2x

y = 20 - 2(5)

y = 20 - 10

y = 10

Therefore, when x = 5, the dependent value y is 10.

Answer:

To find the dependent value (y) for the given graph y = 20 - 2x when the independent value (x) is 5, we substitute x = 5 into the equation and solve for y.

y = 20 - 2x

Substituting x = 5:

y = 20 - 2(5)

y = 20 - 10

y = 10

So, when x = 5, the dependent value (y) is 10.

Answer this math question for 15 points :)

Answers

Answer:

Step-by-step explanation:

use Pythagorean triangle:

a^{2} + b^{2} = c^{2}

a= 12

b= 16

c = ?

12^{2} + 16^{2} = c^{2}

144 + 256 = c^{2}

400 = c^{2}

\sqrt{400} = c

20 = c

c = 20 ft

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