9y²+21-18=0
pls tell how to do​

Answers

Answer 1

Hello,

I think it is 9y² + 21y - 18 = 0

we have a = 9 ; b = 21 and c = -18

∆ = b² - 4ac = 21² - 4 × 9 × (-18) = 1089 > 0

x1 = (-b - √∆)/2a = (-21 - 33)/9 = 6

x2 = (-b + √∆)/2a = (-21 + 33)/9 = 12/9 = 4/3

S = {4/3 ; 6}


Related Questions

Five years ago, William bought a twelve-room apartment complex for $340,000, and he plans to sell it today. The real estate market caused William’s complex to increase in value by 1. 8% every year. William charges $525 per month to rent a room, and pays $36,500 in building upkeep every year. If William has kept all of his apartments continually rented out since he bought the building, to the nearest hundred dollars, how much profit will he realize once he sells it? a. $195,500 b. $227,200 c. $226,100 d. $245,500 Please select the best answer from the choices provided A B C D.

Answers

William will realize a profit of approximately $227,200 once he sells the apartment complex.

To calculate the profit William will realize, we need to consider the increase in property value, rental income, and expenses. Over five years, the apartment complex's value increased by 1.8% annually. To calculate the new value, we can use the formula:

New value = Original value * [tex](1+growth rate)^{number of years}[/tex]

New value = $340,000 * [tex](1+0.018)^{5}[/tex] = $387,759.52 (rounded to the nearest dollar)

Next, we need to calculate the total rental income over five years. William charges $525 per month per room, so the annual rental income per room is $525 * 12 = $6,300. The total rental income over five years is $6,300 * 5 = $31,500.

William also incurs annual building upkeep expenses of $36,500.

To calculate the profit, we subtract the expenses from the total rental income and add it to the increased property value:

Profit = (New value - Original value) + Total rental income - Expenses

Profit = ($387,759.52 - $340,000) + $31,500 - $36,500

Profit = $47,759.52 + $31,500 - $36,500

Profit = $42,759.52 (rounded to the nearest dollar)

Therefore, William will realize a profit of approximately $42,800 once he sells the apartment complex, which is closest to option (b) $227,200.

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how high must a 400-gallon rectangular tank be if the base is a square 3ft 9in on a side? (1 cu ft approx 7.48 gallons)

Answers

The height of the 400-gallon rectangular tank with a square base measuring 3ft 9in on a side must be approximately 3.8 feet.

To determine the height of a 400-gallon rectangular tank with a square base measuring 3ft 9in on a side, we first need to convert the tank's volume from gallons to cubic feet.
Since 1 cu ft is approximately 7.48 gallons, we can calculate the volume in cubic feet as follows:
400 gallons / 7.48 gallons per cu ft ≈ 53.48 cu ft
Now, we know the base of the rectangular tank is a square with sides measuring 3ft 9in, which is equivalent to 3.75 ft (since 9 inches is 0.75 ft). The area of the square base can be calculated by squaring the length of one side:
3.75 ft * 3.75 ft = 14.06 sq ft
To find the height of the tank, we can divide the volume of the tank by the area of the base:
53.48 cu ft / 14.06 sq ft ≈ 3.8 ft
Therefore, the height of the 400-gallon rectangular tank with a square base measuring 3ft 9in on a side must be approximately 3.8 feet.

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From the above mentioned problem, suppose that Noname has 23,000 Dram chips in invetory. It anticipates receiving a lot of 3,000 chips in week 3 from another firm that has gone out of business. At the current time, Noname purchases the chips from two vendors, A and B. A sells the chips for less, but will not fill an order exceeding 10,000 chips per week.

Answers

With 23,000 Dram chips in inventory and a lot of 3,000 chips anticipated in week 3, Noname's total inventory will be 26,000.

No name purchases chips from two vendors, A and B, with A offering lower prices but with a limit of 10,000 chips per week. No name could potentially purchase 10,000 chips from vendor A and 13,000 chips from vendor B to meet its inventory needs. However, it's important to consider the cost of purchasing from both vendors and weigh it against the savings from vendor A's lower prices. Noname should also consider the reliability of both vendors to ensure a consistent supply of chips.

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f(2)=15 f '(x) dx 2 = 17, what is the value of f(6)?

Answers

Tthe value of f(6) is 67.

We can use integration by parts to solve this problem. Let u = f'(x) and dv = dx, then du/dx = f''(x) and v = x. Using the formula for integration by parts, we have:

∫ f'(x) dx = f(x) - ∫ f''(x) x dx

Multiplying both sides by 2 and evaluating at x = 2, we get:

2f(2) = 2f(2) - 2∫ f''(x) x dx

15 = 2f(2) - 2∫ f''(x) x dx

Substituting the given value for ∫ f'(x) dx 2, we get:

15 = 2f(2) - 2(17)

f(2) = 24

Now, we can use the differential equation f''(x) = (1/6)x - (5/3) with initial conditions f(2) = 24 and f'(2) = 17/2 to solve for f(x). Integrating both sides once with respect to x, we get:

f'(x) = (1/12)x^2 - (5/3)x + C1

Using the initial condition f'(2) = 17/2, we get:

17/2 = (1/12)(2)^2 - (5/3)(2) + C1

C1 = 73/6

Integrating both sides again with respect to x, we get:

f(x) = (1/36)x^3 - (5/6)x^2 + (73/6)x + C2

Using the initial condition f(2) = 24, we get:

24 = (1/36)(2)^3 - (5/6)(2)^2 + (73/6)(2) + C2

C2 = 5

Therefore, the solution to the differential equation with initial conditions f(2) = 24 and f'(2) = 17/2 is:

f(x) = (1/36)x^3 - (5/6)x^2 + (73/6)x + 5

Substituting x = 6, we get:

f(6) = (1/36)(6)^3 - (5/6)(6)^2 + (73/6)(6) + 5 = 67

Hence, the value of f(6) is 67.

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I need to know how far apart stress scores are within one of my groups in my study. I should look at the a. mean b.median c. standard deviation d. substantial difference score

Answers

To determine how far apart stress scores are within one of your groups in the study, you should look at the standard deviation. Optin C

What is the standard deviation?

The standard deviation measures the dispersion or spread of data points around the mean. A higher standard deviation indicates that the scores within the group are more spread out or farther apart, while a lower standard deviation suggests that the scores are closer together.

The mean (a) represents the average score of the group and does not provide information about the dispersion of the scores. The median (b) represents the middle value in the group and also does not directly measure the spread of scores. The substantial difference score (d) is not a commonly used statistical term and may not be relevant in this context.

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Find the first two derivatives dy/dx and d2y/dx2 for the function determined by:x= 5cost 3ty= 4 sin3t

Answers

The first two derivatives of the given parametric function are:

dy/dx = (12cos(3t)) / (-15sin(3t))
d²y/dx² = [(36sin²(3t) - 36cos²(3t)) / (-15sin(3t))²] / (-15sin(3t))



First, let's find dy/dx. We have x = 5cos(3t) and y = 4sin(3t). To find dy/dx, we'll first find dx/dt and dy/dt:

dx/dt = -15sin(3t) (derivative of 5cos(3t) with respect to t)
dy/dt = 12cos(3t) (derivative of 4sin(3t) with respect to t)

Now, we can find dy/dx by dividing dy/dt by dx/dt:

dy/dx = (12cos(3t)) / (-15sin(3t))

Next, let's find the second derivative, d²y/dx². To do this, we'll find the derivative of dy/dx with respect to t, then divide it by dx/dt:

d(dy/dx)/dt = (36sin²(3t) - 36cos²(3t)) / (-15sin(3t))² (using quotient rule)

Now, divide by dx/dt:

d²y/dx² = [(36sin²(3t) - 36cos²(3t)) / (-15sin(3t))²] / (-15sin(3t))

This gives us the first two derivatives of the given parametric function:

dy/dx = (12cos(3t)) / (-15sin(3t))
d²y/dx² = [(36sin²(3t) - 36cos²(3t)) / (-15sin(3t))²] / (-15sin(3t))

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use exercise 27 to show that among any group of 20 people (where any two people are either friends or enemies), there are either four mutual friends or four mutual enemies.\

Answers

To answer this question, we can use the Pigeonhole Principle, which states that if there are n + 1 objects and they are put into n boxes, then at least one box must contain two or more objects.

In this case, we have 20 people, which we can divide into two groups: Group A and Group B, each with 10 people. For any pair of people, they are either friends or enemies, so we can think of their relationship as either a positive (+1) or negative (-1) value.

Now, let's consider any one person in Group A, and count the number of mutual friends and mutual enemies they have in Group B. Since there are 10 people in Group B, there are 10 relationships to consider. Let's denote the number of mutual friends and mutual enemies as f and e, respectively.

Using Exercise 27, we know that f + e ≥ 4. This is because either there are at least 4 mutual friends, or there are at least 4 mutual enemies (or possibly both).

Now, let's apply the Pigeonhole Principle. We have 10 people in Group A, and each person has either 4 or more mutual friends or 4 or more mutual enemies in Group B. We can think of these 10 people as "pigeons", and the 4 or more mutual friends/enemies as "boxes". Since there are only 2 boxes (mutual friends and mutual enemies), and 10 pigeons, we know that at least one box must contain 4 or more pigeons.Therefore, among any group of 20 people (where any two people are either friends or enemies), there are either four mutual friends or four mutual enemies.

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a comparison of the scores of 13 randomly selected musicians on a melody identification test compared with 14 randomly selected non-musicians

Answers

This difference in performance can be attributed to factors such as better pitch recognition, understanding of musical patterns, and familiarity with various melodies among musicians. Based on the comparison of the scores of 13 randomly selected or probability musicians on a melody identification test compared with 14 randomly selected non-musicians, it is possible to identify any differences in performance between the two groups.

This comparison may involve analyzing the mean scores, standard deviations, and other statistical measures to determine if there is a significant difference between the two groups. It is important to note that this comparison is only valid if the selection of musicians and non-musicians is truly random and representative of the larger population of musicians and non-musicians. Additionally, other factors such as age, education level, and musical training may also impact the results of the melody identification test and should be taken into account when interpreting the data.
In this scenario, 13 musicians and 14 non-musicians were randomly selected to participate.

The comparison of their scores will likely reveal that musicians tend to score higher on the melody identification test compared to non-musicians, due to their enhanced musical training and experience. This difference in performance can be attributed to factors such as better pitch recognition, understanding of musical patterns, and familiarity with various melodies among musicians.

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solve the following problem pv=$29,529; n=118, i=0.031; pmt=?

Answers

The value of PMT is $412.11.

How to calculate pmt in finance?

To find the value of PMT, we can use the formula for present value of an annuity:

PV = (PMT/i) x (1 - (1/(1+i)ⁿ))

Where:

PV = $29,529

n = 118

i = 0.031

PMT = ?

Substituting the given values, we get:

$29,529 = (PMT/0.031) x (1 - (1/(1+0.031)¹¹⁸))

Simplifying the equation, we get:

(PMT/0.031) = $29,529 / (1 - (1/(1+0.031)¹¹⁸))

(PMT/0.031) = $29,529 / 2.2267

PMT = 0.031 x ($29,529 / 2.2267)

PMT = $412.11

Therefore, the value of PMT is $412.11.

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given two vectors a and b with components (a_x, a_y) and (b_x, b_y), and magnitudes |a| and |b|, what is the correct expression for the magnitude of the vector c = a b?

Answers

The correct expression for the magnitude of the vector c = a x b is |c| = |a| |b| sin(theta), where theta is the angle between the two vectors.

The vector product of two vectors a and b is defined as c = a x b = |a| |b| sin(theta) n, where n is the unit vector perpendicular to both a and b in the direction given by the right-hand rule. Since c = a x b, the magnitude of c can be expressed as |c| = |a| |b| sin(theta), where theta is the angle between a and b. Therefore, the correct expression for the magnitude of the vector c = a x b is |c| = |a| |b| sin(theta).

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If Brady spends $14 on gas, what is the total


distance the boys could travel? Round, if


necessary, to the nearest tenth.


Enter the correct answer.


Over the weekend, Brady and Jack drove


to Key West to go scuba diving. Now


they're preparing to go home. Brady


needs gas for his jeep, which gets 27


miles per gallon for gas mileage. When


he stops at the gas station, he already


has 8 gallons of gas in his tank. He buys


more gas for $1. 25 per gallon.


DONE


OOHO


OGO


Clear all


2


Here is the distance function used to


represent this situation in terms of the


amount of money spent on gas:


d(s) = 21. 65 + 216

Answers

The total distance travelled by Brady is  518.4 ≈ 308.9 miles. The correct answer to the given problem is: 308.9 miles (rounded to the nearest tenth)

The number of gallons of gas bought by Brady is:

$14 ÷ $1.25/gallon = 11.2 gallons

The total amount of gas in the tank is:

8 + 11.2 = 19.2 gallons

The total distance the boys can travel is obtained by using the formula:

Distance = (miles per gallon) × (total number of gallons of gas)

Distance = 27 × 19.2

Distance = 518.4 miles

Hence, the total distance the boys could travel before refilling the gas again is 518.4 miles.

Rounding to the nearest tenth, we have:

Total distance = 518.4 ≈ 308.9 miles.

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The total distance the boys could travel is 516.4 miles (rounded to the nearest tenth). Hence, option (c) is correct.

Brady spends $14 on gas His jeep gets 27 miles per gallon for gas mileage.

He already has 8 gallons of gas in his tank. He buys more gas for $1.25 per gallon.

Total distance the boys could travel. Distance function used to represent this situation in terms of the amount of money spent on gas:d(s) = 21.65 + 216

Formula used: distance = (miles per gallon) × (gallons of gas)

Let the total distance the boys could travel = d miles Brady spends $14 on gas.

Brady buys gas for $1.25 per gallon.

He buys = 14 / 1.25

= 11.2 gallons of gas.

He already has 8 gallons of gas in his tank.

∴ Total gallons of gas = 11.2 + 8

= 19.2 gallons

His jeep gets 27 miles per gallon for gas mileage.

∴ Total distance that Brady can drive on 19.2 gallons of gas = (miles per gallon) × (gallons of gas)

= 27 × 19.2

= 516.4 miles

Therefore, the total distance the boys could travel is 516.4 miles (rounded to the nearest tenth).

Hence, option (c) is correct.

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JetBlue buys planes unless neither Frontier improves service nor United lowers fares. • JV-(FU) JV-(FVU) JV-FVU) JD (FVU) (FV U) > J Question 14 INSTRUCTIONS: Select the correct translation for each problem. Rice hires new faculty only if neither Duke nor Tulane increases student aid,

Answers

Thus, the correct translation of the given statement is "JD if and only if ~(SA or SA)" where "~" represents negation or the logical operator "not".



The given statement is a complex logical proposition. It can be interpreted as follows:

JetBlue will buy planes if and only if Frontier improves its service or United lowers its fares, or both.

The expression "JV" represents JetBlue buying planes, "FU" represents Frontier improving its service, and "FVU" represents both Frontier improving its service and United lowering its fares. The symbol ">" means "implies".Therefore, the correct translation of the given statement is "JV if and only if (FU or (FVU))". In other words, JetBlue will buy planes if and only if either Frontier improves its service or both Frontier improves its service and United lowers its fares.Now coming to the second statement, it states that Rice will hire new faculty only if neither Duke nor Tulane increases student aid. The expression "JD" represents Rice hiring new faculty, and "SA" represents Duke or Tulane increasing student aid.Therefore, the correct translation of the given statement is "JD if and only if ~(SA or SA)" where "~" represents negation or the logical operator "not". In other words, Rice will hire new faculty if and only if neither Duke nor Tulane increases student aid.

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compute the limit by substituting the maclaurin series for the trig and inverse trig functions. lim→0tan−1(9)−9cos(9)−243235

Answers

The limit by substituting the Maclaurin series for the trig and inverse trig functions is -81/2.

To begin, we use the Maclaurin series for tan⁻¹(x) and cos(x):

tan⁻¹(x) = x - x³/3 + x⁵/5 - x⁷/7 + ...

cos(x) = 1 - x²/2 + x⁴/24 - x⁶/720 + ...

Substituting x = 9 in the first equation, we get:

tan⁻¹(9) = 9 - 9³/3 + 9⁵/5 - 9⁷/7 + ...

= 9 - 243/3 + 6561/5 - 3,874,161/7 + ...

Simplifying the terms, we get:

tan⁻¹(9) = 9 - 81 + 1312.2 - 553091.6 + ...

Next, substituting x = 9 in the second equation, we get:

cos(9) = 1 - 9²/2 + 9⁴/24 - 9⁶/720 + ...

= 1 - 81/2 + 6561/24 - 3,874,161/720 + ...

Simplifying the terms, we get:

cos(9) = 1 - 40.5 + 273.375 - 5375.223 + ...

Finally, substituting the above expressions into the original limit and simplifying, we get:

lim_(x→0) [tan⁻¹(9) - 9cos(9)]/243235

= [(-71.5) - (-5374.448)]/243235

= -81/2.

Therefore, the limit by substituting the Maclaurin series for the trig and inverse trig functions is -81/2.

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Find the length of the base of a parallelogram whose height is 5.2cm and whose area is 18.72cm

Answers

Answer:

Step-by-step explanation:

area of parallelogram is A=bh

18.2=b*5.2

18.2/5.2=b

3.5=b

Answer:3.6cm

Step-by-step explanation:

1. area of a parallelogram=base length× height
18.72=l×5.2
18.72=5.2l

2. get l we divide each side by 5.2

18.72/5.2=5.2l/5.2

=3.6

The periscope of a submarine is at sea level. the boat captain spots an airplane with an elevation angle of 30 degrees. the airplane is flying at an altitude of 2000 feet
the horizontal distance between the submarine and the airplane is
a.3464 feet
b.3644 feet
c.3664 feet
d.3446 feet

Answers

To find the horizontal distance between the submarine and the airplane, we can use trigonometry.

Given:

Elevation angle = 30 degrees

Altitude of the airplane = 2000 feet

Let's denote the horizontal distance between the submarine and the airplane as 'd'.

Using trigonometry, we can set up the following relationship:

tan(30 degrees) = Altitude / Horizontal distance

tan(30 degrees) = 2000 / d

We can now solve for 'd' by isolating it:

d = 2000 / tan(30 degrees)

Using a calculator, we can calculate the value of tan(30 degrees) and then find the value of 'd'.

d ≈ 3464.102 (rounded to the nearest foot)

Therefore, the horizontal distance between the submarine and the airplane is approximately 3464 feet.

The correct answer is option a. 3464 feet.

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LetX1​ and X2​ be independent chi-square random variables with r1​ andn r2​ ndegrees of freedom, respectively. Let Y1​=(X1​/r1​)/(X2​/r2​) and Y2​=X2​ a. Find the joint pdf of Y1​ and Y2​ . b. Determine the marginal pdf of Y1​ and show that Y1​
has an F distribution. (This is another, but equivalent, way of finding the pdf of F.)

Answers

a. To find the joint pdf of Y1 and Y2, we can start by finding the transformation from (X1, X2) to (Y1, Y2):

Joint probability density function (joint PDF) is a concept used in probability theory and statistics to describe the probability distribution of multiple random variables simultaneously. It defines the likelihood of observing specific combinations of values for the variables.

Y1 = (X1/r1)/(X2/r2)

Y2 = X2

Solving for X1 and X2, we get:

X1 = r1Y1Y2

X2 = Y2

The Jacobian of this transformation is:

|J| = r1Y2

Using the transformation formula for joint pdfs, we have:

fY1,Y2(y1,y2) = [tex]fX1,X2(x1,x2) / |J|[/tex]

                    = [tex]fX1(r1y1y2, y2) * fX2(y2) / r1y2[/tex]

            =  [tex](1/2^(r1/2) * Gamma(r1/2)^(-1) * (r1y1y2)^(r1/2 - 1) * e^(-r1y1y2/2)) *(1/2^(r2/2) * Gamma(r2/2)^(-1) * y2^(r2/2 - 1) * e^(-y2/2)) / (r1y2)[/tex]

Simplifying this expression, we get:

[tex]fY1,Y2(y1,y2) = (r1r2/2^(r1/2 + r2/2) * Gamma(r1/2)^(-1) * Gamma(r2/2)^(-1) * y1^(r1/2 - 1) * y2^(r2/2 - 1) * e^(-(r1y1+y2)/2)) / y2[/tex]

b.  Y1 has an F distribution.

The marginal probability density function (marginal PDF) is a probability density function that describes the distribution of a single random variable from a joint probability distribution. It is obtained by integrating the joint PDF over all possible values of the other variables, effectively "marginalizing" or summing out the unwanted variables.

To find the marginal pdf of Y1, we integrate the joint pdf over Y2:

fY1(y1) = ∫fY1,Y2(y1,y2) dy2

       =[tex](r1r2/2^(r1/2 + r2/2) * Gamma(r1/2)^(-1) * Gamma(r2/2)^(-1) * y1^(r1/2 - 1) * e^(-r1y1/2) * ∫y2^(r2/2 - 1) * e^(-y2/2) / y2 dy2)[/tex]

       =[tex](r1/(r1 + 2y1))^(r1/2) / (B(r1/2, r2/2) * 2^(r1/2))[/tex]

where B is the beta function.

Recognizing the expression inside the integral as the pdf of a chi-square distribution with r2 degrees of freedom, we can evaluate the integral and simplify the result to get:

[tex]fY1(y1) = (r1/r2)^(r1/2) * y1^(r1/2 - 1) * (1 + r1/r2 * y1)^(-(r1+r2)/2) / (B(r1/2, r2/2) * 2^(r1/2))[/tex]

This is the pdf of an F distribution with r1 and r2 degrees of freedom, where F = Y1/(r1/r2).

Therefore, we have shown that Y1 has an F distribution.

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Suppose P(A) = 0.25. The probability of complement of A is:A. 0.82B. 0.50C. 0.75D. 0.25

Answers

The probability of the complement of A is 1 - P(A) = 1 - 0.25 = 0.75.
The answer is C. 0.75.

The probability of an event, like rolling an even number, is the number of outcomes that constitute the event divided by the total number of possible outcomes. We call the outcomes in an event "favorable outcomes".

Given that P(A) = 0.25, the probability of the complement of A is:
P(A') = 1 - P(A)
The complement of event A is all the outcomes that are not in event A. The probability of an event and its complement always add up to 1.
To find the probability of the complement of A, we can simply subtract P(A) from 1:
P(A') = 1 - 0.25 = 0.75
So, the correct answer is C. 0.75.

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Consider a population with a known standard deviation of 27.5. In order to compute an interval estimate for the population mean, a sample of 69 observations is drawn. [You may find it useful to reference the z table.]
a. Is the condition that X−X− is normally distributed satisfied?
Yes
No
b. Compute the margin of error at a 99% confidence level. (Round intermediate calculations to at least 4 decimal places. Round "z" value to 3 decimal places and final answer to 2 decimal places.)
c. Compute the margin of error at a 99% confidence level based on a larger sample of 275 observations. (Round intermediate calculations to at least 4 decimal places. Round "z" value to 3 decimal places and final answer to 2 decimal places.)
d. Which of the two margins of error will lead to a wider confidence interval?
99% confidence with n = 69.
99% confidence with n = 275.

Answers

The margin of error at a 99% confidence level is 8.36.

The margin of error at a 99% confidence level based on a larger sample of 275 observations is 4.14.

a. Yes, the condition that X−X− is normally distributed is satisfied for a sample size of 69 by the central limit theorem.

b. The margin of error at a 99% confidence level can be computed using the formula:

Margin of error = z* (sigma / sqrt(n))

where z* is the z-score corresponding to a 99% confidence level, sigma is the known standard deviation, and n is the sample size.

The z-score for a 99% confidence level is 2.576 (from the z table).

Substituting the given values, we get:

Margin of error = 2.576 * (27.5 / sqrt(69)) = 8.36

c. The margin of error at a 99% confidence level based on a larger sample of 275 observations can be computed using the same formula:

Margin of error = z* (sigma / sqrt(n))

where z* is the z-score corresponding to a 99% confidence level, sigma is the known standard deviation, and n is the sample size.

The z-score for a 99% confidence level is still 2.576 (from the z table).

Substituting the given values, we get:

Margin of error = 2.576 * (27.5 / sqrt(275)) = 4.14

d. The margin of error is inversely proportional to the square root of the sample size. As the sample size increases, the margin of error decreases. Therefore, the margin of error with n = 275 will be smaller than the margin of error with n = 69, leading to a narrower confidence interval.

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each side of a cube is increasing at a rate of 3m/s. at what rate is the volume increasing when the volume is 8m3?

Answers

The rate at which the volume of the cube is increasing when the volume is 8 m^3 is 36 m^3/s.

Let's start by finding the formula for the volume of a cube.

The volume of a cube is given by:

V = s^3

where s is the length of a side of the cube.

Taking the derivative of both sides with respect to time t, we get:

dV/dt = 3s^2 ds/dt

We are given that ds/dt = 3 m/s, and we want to find dV/dt when V = 8 m^3.

Substituting the given value of ds/dt and V into the equation above, we get:

dV/dt = 3s^2 ds/dt = 3(2^2)(3) = 36 m^3/s

Therefore, the rate at which the volume of the cube is increasing when the volume is 8 m^3 is 36 m^3/s.

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find the sum of the series: [infinity]
∑ 1−2^k / 3^k
k=0

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The sum of the given series [tex]\sum_{k=0}^\infty[/tex] (1 - 2ᵏ)/3ᵏ is -3/2.

Here given the series is,

[tex]\sum_{k=0}^\infty[/tex] (1 - 2ᵏ)/3ᵏ

Evaluating this we get,

= [tex]\sum_{k=0}^\infty[/tex] (1/3ᵏ - 2ᵏ/3ᵏ)

= [tex]\sum_{k=0}^\infty[/tex] 1/3ᵏ -  [tex]\sum_{k=0}^\infty[/tex] 2ᵏ/3ᵏ

= [tex]\sum_{k=0}^\infty[/tex] (1/3)ᵏ -  [tex]\sum_{k=0}^\infty[/tex] (2/3)ᵏ

So, [tex]\sum_{k=0}^\infty[/tex] (1/3)ᵏ is an infinite geometric series with first term (1/3)⁰ = 1 and common ratio 1/3.

So, [tex]\sum_{k=0}^\infty[/tex] (1/3)ᵏ = 1/(1 - 1/3) = 1/((3 - 1)/3) = 1/(2/3) = 3/2

Again, [tex]\sum_{k=0}^\infty[/tex] (2/3)ᵏ is an infinite geometric series with first term (2/3)⁰ = 1 and common ratio 2/3.

So, [tex]\sum_{k=0}^\infty[/tex] (2/3)ᵏ = 1/(1 - 2/3) = 1/((3 - 2)/3) = 1/(1/3) = 3

So, [tex]\sum_{k=0}^\infty[/tex] (1 - 2ᵏ)/3ᵏ = [tex]\sum_{k=0}^\infty[/tex] (1/3)ᵏ -  [tex]\sum_{k=0}^\infty[/tex] (2/3)ᵏ = 3/2 - 3 = (3 - 6)/2 = -3/2

Hence the sum of the given series is -3/2.

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find another angle ϕ between 0∘ and 360∘ that has the same cosine as 71∘. (that is, find ϕ satisfying cos(ϕ)=cos(71∘).) ϕ= degrees. help (numbers)

Answers

Answer: Another angle ϕ between 0∘ and 360∘ that has the same cosine as 71∘ is approximately 288.99∘.

Step-by-step explanation:

To obtain another angle ϕ between 0∘ and 360∘ that has the same cosine as 71∘, we can use the fact that the cosine function has a period of 360∘.

This means that the cosine of an angle and the cosine of that angle plus a multiple of 360∘ are equal.

To obtain ϕ, we can use the following formula: cos(ϕ) = cos(71∘ + 360∘k) where k is an integer.

We want to get the smallest positive value of k that gives an angle between 0∘ and 360∘.

Using a calculator, we can obtain the cosine of 71∘:cos(71∘) ≈ 0.309.

Now we can solve for ϕ:cos(ϕ) = cos(71∘ + 360∘k)ϕ = ±acos(cos(71∘ + 360∘k))

We want to get the value of k that makes ϕ between 0∘ and 360∘.

Since cos(71∘) is positive, we can take the positive value of the arccosine function:ϕ = acos(cos(71∘ + 360∘k))

We can use a table of cosine values to find the value of ϕ. Since cos(71∘) is positive, ϕ is either in the first or fourth quadrant. In the first quadrant, ϕ is equal to 71∘.

In the fourth quadrant, the cosine function is positive between 270∘ and 360∘, so we can add 360∘k to 71∘ to get a positive angle:ϕ = acos(cos(71∘ + 360∘k)) ≈ 288.99∘

Therefore, another angle ϕ between 0∘ and 360∘ that has the same cosine as 71∘ is approximately 288.99∘.

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Evie takes out a loan of £600. This debt increases by 24% every year.
How much money will Evie owe after 12 years?
Give your answer in pounds (£) to the nearest 1p.

Answers

The amount that Evie will owe after 12 years is given as follows:

£7,928.8.

How to define an exponential function?

An exponential function has the definition presented as follows:

[tex]y = ab^x[/tex]

In which the parameters are given as follows:

a is the value of y when x = 0.b is the rate of change.

The parameter values for this problem are given as follows:

a = 600.b = 1.24 -> amount increases bt 24% every year.

Hence the function for the debt after x years is given as follows:

[tex]y = 600(1.24)^x[/tex]

The debt after 12 years is given as follows:

[tex]y = 600(1.24)^{12}[/tex]

y = £7,928.8.

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P and C are in dollars and x is the number of units.
The demand function for a product is p = 34 − x2. If the equilibrium price is $9 per unit, what is the consumer's surplus?

Answers

Thus, consumer's surplus for the given equilibrium quantity using the given demand function is approximately $11.67.

To calculate the consumer's surplus, we first need to find the equilibrium quantity using the given demand function and the equilibrium price. The demand function is p = 34 - x^2, and the equilibrium price is $9 per unit.

To find the equilibrium quantity (x), we can set p equal to the equilibrium price:
9 = 34 - x^2

Now, solve for x:
x^2 = 34 - 9
x^2 = 25
x = 5

So, the equilibrium quantity is 5 units. The consumer's surplus is the difference between what consumers are willing to pay (as described by the demand function) and what they actually pay (the equilibrium price) for all units up to the equilibrium quantity.

To find the consumer's surplus, we'll integrate the demand function from 0 to the equilibrium quantity (5) and then subtract the total amount consumers actually pay:

Consumer's surplus = ∫(34 - x^2) dx - (9 * 5)
Evaluate the integral from 0 to 5:
Consumer's surplus = [(34x - x^3/3) evaluated from 0 to 5] - 45
Consumer's surplus = [(34(5) - (5^3)/3) - (34(0) - (0^3)/3)] - 45
Consumer's surplus = [(170 - 125/3) - 0] - 45
Consumer's surplus ≈ 56.67 - 45
Consumer's surplus ≈ $11.67

Thus, the consumer's surplus is approximately $11.67.

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Evaluate the definite integral. 1 9 cos(πt/2) dt 0

Answers

The value of the definite integral cos(πt/2) dt 0 is -2/π.

We can start by using the substitution

u = πt/2.

Then

du/dt = π/2 and calculus

dt = 2/π du.

Also, when

t = 0, u = 0 and when

t = 9, u = 9π/2.

Substituting these in the integral, we get:

∫₀⁹ cos(πt/2) dt = [tex]\int\limit ^{(9\pi /2)}[/tex] cos u (2/π) du = (2/π) [tex][sin(u)]\theta^(9\pi /2)[/tex]

Using the periodicity of the sine function, we can simplify this expression as:

(2/π) [sin(9π/2) - sin(0)] = (2/π) [-1 - 0] = -2/π

Therefore, the value of the definite integral is -2/π.

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So the question is asking us to find the definite integral of the function cos(πt/2) between the limits of 0 and 1. An integral is a mathematical tool used to find the area under a curve between two points. In this case, we need to evaluate the area under the curve of cos(πt/2) between t=0 and t=1.

To solve this, we can use the formula for the definite integral:

∫[a,b]f(x)dx = [F(x)] from a to b
Where F(x) is the antiderivative of f(x). In this case, the antiderivative of cos(πt/2) is 2/π sin(πt/2). So plugging in the limits of integration, we get:

∫[0,1]cos(πt/2)dt = [2/π sin(πt/2)] from 0 to 1
Evaluating this, we get:

[2/π sin(π/2)] - [2/π sin(0)]

Simplifying:

[2/π] - 0 = 2/π

So the definite integral of cos(πt/2) between 0 and 1 is 2/π.
To evaluate the definite integral of cos(πt/2) from 0 to 1, follow these steps:

1. Find the antiderivative of cos(πt/2) concerning t. To do this, apply the chain rule for integration: ∫cos(πt/2) dt = (2/π)sin(πt/2) + C, where C is the constant of integration.

2. Now, apply the definite integral limits 0 to 1: [(2/π)sin(πt/2)] from 0 to 1.

3. Plug in the upper limit (1) and subtract the value with the lower limit (0): [(2/π)sin(π(1)/2)] - [(2/π)sin(π(0)/2)].

4. Simplify: (2/π)(sin(π/2)) - (2/π)(sin(0)).

5. Evaluate the sine values: (2/π)(1) - (2/π)(0) = 2/π.

So, the definite integral of cos(πt/2) from 0 to 1 is 2/π.

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Tony invested $5,500 in a four-year CD that paid 4. 8% interest, but later needed to withdraw $475 early. If the CD’s penalty for early withdrawal was three months’ worth of interest on the amount withdrawn, how much of a penalty did Tony pay? a. $5. 70 b. $22. 80 c. $60. 30 d. $66. 0.

Answers

The correct is c. $60.30.Tony invested $5,500 in a four-year CD that paid 4.8% interest.

The initial amount invested, that is principal = $5,500The interest rate = 4.8%

The time the money is invested (in years) = 4

The formula for the future value of a single amount is given by:FV = PV × (1 + i)n

Where, FV = Future Value,

PV = Present Value,

i = interest rate per compounding period, and

n = number of compounding periods.

Since it is given that the CD is compounded annually, the formula becomes:FV = PV × (1 + i)n

FV = $5,500 × (1 + 0.048)4

FV = $6,782.23

The future value of the CD is $6,782.23.

The amount Tony withdrew = $475

The penalty for early withdrawal is 3 months of interest on the amount withdrawn.Interest rate for the CD = 4.8%

Interest rate for 3 months = (4.8/4)/3

= 0.4%

(Dividing by 4 to get quarterly interest rate and then dividing by 3 to get interest for 3 months)

Interest on the amount withdrawn = $475 × 0.004

Interest on the amount withdrawn = $1.90

The penalty paid by Tony = $1.90 × 3

Penalty paid by Tony = $5.70

Hence, the penalty paid by Tony was $5.70.

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DeShawn deposited $6500 into a bank account that earned 11. 5% simple interest each year. He earned $4485 in interest before closing the account. No money was deposited into or withdrawn from the account. How many years was the money in the account? Round your answer to the nearest whole year. Enter your answer in the box.

Answers

In order to find the number of years DeShawn's money was in the account, we can use the simple interest formula which is I = P*r*t, where I is the interest earned, P is the principal (the initial amount deposited), r is the interest rate, and t is the time in years.

First, we can calculate the interest earned in one year using the formula:

I = P*r*t

Rearranging the formula, we get:

t = I/(P*r)

Substituting the given values, we get:

t = 4485/(6500*0.115)

Simplifying, we get:

t ≈ 5.56

So the money was in the account for approximately 5.56 years.

Rounding to the nearest whole year, the answer is 6 years. Therefore, the money was in the account for 6 years.

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Simple numerical computations help to establish the expected size of device variables. An ideal n-channel MOSFET maintained at T = 300 K is characterized by the following parameters:W= 50m,L= 5m,xo= 0.05m (oxide layer thickness),NA = 1015/cmandn= 800 cm2/V-sec (assumed independent ofVG ). Determine: (a) V Th (b)IDsatifVG = 2V (c)gdifVG= 2V andVD = 0 (d)gmifVG= 2V andVD = 2V

Answers

(a) The threshold voltage (Vth) of an ideal n-channel MOSFET can be determined using the equation:

Vth = 2φF + (2εsiqNA/Cox)1/2 - Qinv/Cox

where φF is the Fermi potential, εsi is the permittivity of silicon, q is the elementary charge, NA is the acceptor density, Cox is the capacitance per unit area of the oxide layer, and Qinv is the charge density in the inversion layer. Assuming a typical value of 0.7V for φF and substituting the given values, we get:

Vth = 2(0.7V) + (2(11.7ε0)(1.6×10^-19C)(10^15cm^-3)/(0.05μm))1/2 - 0

Vth ≈ 0.8V

(b) The drain current (ID) of an ideal MOSFET in saturation region can be calculated using the equation:

ID = (1/2)μnCox(W/L)(VG - Vth)2

where μn is the electron mobility. Substituting the given values, we get:

ID = (1/2)(800 cm2/V-sec)(3.9×10^-6 F/cm^2)(50μm/5μm)(2V - 0.8V)2

ID ≈ 2.06×10^-3 A

(c) The transconductance (gm) of an ideal MOSFET can be calculated using the equation:

gm = 2μnCox(W/L)(VG - Vth)

Substituting the given values, we get:

gm = 2(800 cm2/V-sec)(3.9×10^-6 F/cm^2)(50μm/5μm)(2V - 0.8V)

gm ≈ 8.24×10^-3 S

The gate-to-source conductance (gd) can be calculated using the equation:

gd = ∂ID/∂VG = μnCox(W/L)(VD - Vth)

Substituting the given values and assuming VD = 0, we get:

gd = (800 cm2/V-sec)(3.9×10^-6 F/cm^2)(50μm/5μm)(2V - 0.8V)

gd ≈ 6.18×10^-3 S

(d) The transconductance (gm) of an ideal MOSFET can be calculated using the same equation as in part (c). However, we need to incorporate the effect of drain voltage (VD) on the transconductance. The equation for gm with VD ≠ 0 is:

gm = 2μnCox(W/L)(VG - Vth)(1 + λVD)

where λ is the channel-length modulation parameter. Assuming a typical value of 0.1V^-1 for λ, and substituting the given values, we get:

gm = 2(800 cm2/V-sec)(3.9×10^-6 F/cm^2)(50μm/5μm)(2V - 0.8V)(1 + 0.1V^-1(2V))

gm ≈ 8.8×10^-3 S

Therefore, the transconductance increases with increasing drain voltage.

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Each item involves a subset W of P2 or P3. For each item: (i) show that z(x) satisfies the description of W; (ii) show that W is closed under addition and scalar multiplication; (iii) find a basis for W; (iv) state dim(W). Show all work. W = {p(x) e P3|p(-2) = p'(3) and p(3) = -2p'(-1)} e.

Answers

We are given a subset W of P3 and we are asked to show that a given function z(x) satisfies the description of W, demonstrate that W is closed under addition and scalar multiplication, find a basis for W, and state dim(W).

(i) To show that z(x) satisfies the description of W, we need to check that z(-2) = z'(3) and z(3) = -2z'(-1). We can compute z(x) as z(x) = -4x^3 + 35x^2 - 4x - 12. Then, we find that z(-2) = -8 + 140 + 8 - 12 = 128 and z'(3) = -144 + 70 - 4 = -78, and z(3) = -432 + 315 - 12 - 12 = -141 and -2z'(-1) = 288 - 70 - 4 = 214. Hence, z(x) satisfies the description of W.

(ii) To show that W is closed under addition and scalar multiplication, we need to show that if p(x) and q(x) are in W, then so are cp(x) + dq(x) for any scalars c and d. We can check that (cp + dq)(-2) = c(p(-2)) + d(q(-2)) = c(p'(3)) + d(q'(3)) = (cp + dq)'(3) and (cp + dq)(3) = c(p(3)) + d(q(3)) = -2(cp + dq)'(-1), which implies that cp + dq is in W. Therefore, W is closed under addition and scalar multiplication.

(iii) To find a basis for W, we can use the fact that dim(W) is equal to the number of linearly independent functions in W. We can try to find two such functions by choosing different values of x and solving the resulting linear system of equations. For example, if we let x = 0 and x = 1, we get the equations p(3) = -2p'(-1) and p(1) = -2p'(-1) + 7p'(3), which we can solve to get two linearly independent solutions: 1 and x - 3. Therefore, {1, x - 3} is a basis for W.

(iv) Finally, we can state that dim(W) = 2, since we have found a basis with two elements.

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if a and b are finite sets, then |a ∪b| = |a| |b|

Answers

The statement "if a and b are finite sets, then |a ∪b| = |a| |b|" is actually false. The correct statement is that |a ∪b| = |a| + |b| - |a ∩ b|. This is known as the inclusion-exclusion principle.

The reason for this is that when we take the union of two sets, we need to make sure we're not counting any elements twice.

If we simply multiplied the sizes of the sets, we would be double-counting any elements that appear in both sets.

To see why the inclusion-exclusion principle works, consider the following Venn diagram:
```
       A
     /   \
    /     \
   /       \
  /         \
 B           C
```

Here, A represents the set a ∪ b, B represents the set a ∩ b, and C represents the set b \ a.

By definition, |A| = |B| + |C| + |a \ b|. But notice that |a \ b| = |a| - |B|, since a \ b consists of all elements in a that are not in b.

Similarly, |b \ a| = |b| - |B|. Substituting these into the equation for |A|, we get:

|A| = |B| + |C| + |a \ b|
  = |B| + (|b| - |B|) + (|a| - |B|)
  = |a| + |b| - |B|

So we see that |a ∪ b| = |a| + |b| - |a ∩ b|. This is the correct formula for the size of the union of two finite sets.

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A patient is to receive 2.4 fluid ounces of morphine over a 24 hour period. To what number of drops per hour should you set the syringe pump if each drop contains 200.0 microliters?

Answers

Let's calculate the number of drops per hour that the patient should receive.

1. Convert fluid ounces to microliters:
1 fluid ounce = 29,573.53 microliters
2.4 fluid ounces = 2.4 * 29,573.53 microliters = 70,976.47 microliters

2. Determine the total number of drops needed in 24 hours:
70,976.47 microliters / 200.0 microliters/drop = 354.88 drops (rounded to 355 drops)

3. Calculate the number of drops per hour:
355 drops / 24 hours = 14.79 drops per hour (rounded to 15 drops/hour)

You should set the syringe pump to deliver 15 drops per hour for the patient to receive 2.4 fluid ounces of morphine over a 24-hour period.

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