cos(x/3)cos(x/3=1/2[1+cos(2x/3)] true or false

Cos(x/3)cos(x/3=1/2[1+cos(2x/3)] True Or False

Answers

Answer 1

Answer:

Step-by-step explanation:

False.

The correct identity is:

cos^2(x/3) = 1/2[1+cos(2x/3)]

To see why, use the double angle formula for cosine:

cos(2x/3) = 2cos^2(x/3) - 1

Substitute this into the original equation:

cos(x/3)cos(x/3) = 1/2[1+2cos^2(x/3)-1]

Simplify:

cos^2(x/3) = 1/2[1+cos(2x/3)]

Answer 2

Answer:

Statement is true!

Step-by-step explanation:

Required to Prove:

[tex]\Large \textsf{$\cos \left(\frac{x}{3}\right)\cos \left(\frac{x}{3} \right)=\frac{1}{2} \left[1+\cos(\frac{2x}{3})\right]$}[/tex]

This is a special property, used in integral calculus, that can be derived and hence proved, from the double angle formula of cosine.

[tex]\large \textsf{Given that cos(A+B) = cosA\,cosB $-$ sinA\,sinB,}\\ \\\large \textsf{Hence cos(A+A) = cosA\,cosA $-$ sinA\,sinA}\\ \\\large \textsf{$\therefore$ cos2A = cos$^2$A $-$ sin$^2$A}\\ \large \textsf{$\rm \phantom{\therefore cos^2A}=$ 1 $-$ 2sin$^2$A}\\ \large \textsf{$\rm \phantom{\therefore cos^2A}=$ 2cos$^2$A $-$ 1 (using Pythagorean Identity $\Rightarrow cos^2A+sin^2A = 1$)}[/tex]

This property, can be quoted in exams and only has to be derived, not proved. Now using the Cos2A property, we can manipulate the formula:

[tex]\large \textsf{$\cos2\rm A = \cos^2A - \sin^2A$}\\ \\ \large \textsf{$\rm \phantom{\cos 2A}=2\cos^2A-1$}\\ \\ \large \textsf{$\rm \therefore \cos2A+1 = 2\cos^2A$}\\ \\ \large \textsf{$\rm \cos^2A=\frac{\cos2A+1}{2}$}\\ \\ \large \textsf{$\rm \phantom{\cos^2A}=\frac{1}{2}(\cos2A+1)$}\\ \\ \large \textsf{$\rm \phantom{\cos^2A}=\frac{1}{2}(1+\cos2A)$}[/tex]

And since:

[tex]\large \textsf{$\cos \left(\frac{x}{3}\right)\cos\left(\frac{x}{3}\right)=\cos^2\left(\frac{x}{3}\right)$}[/tex]

Therefore, inputting the value of A = [tex]\Large \textsf{$\frac{x}{3}$}[/tex] into the formula we derived above, hence:

[tex]\Large \boxed{\boxed{\textsf{$\cos \left(\frac{x}{3}\right)\cos \left(\frac{x}{3} \right)=\frac{1}{2} \left[1+\cos(\frac{2x}{3})\right]$}}} \Large \textsf{ , as required}[/tex]

∴ Statement is true

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Related Questions

A soccer goal is 8 yards wide. Suppose a goalie is standing on her line in
the center of her goal as a striker from the opposing team moves the ball
towards her. The near post angle, a, is formed by rays extending from the
ball to the near post and the goalie. Similarly, the far post angle, ß, is
formed by rays extending from the ball to the far post and the goalie. See
the figure.
a) Determine the near post angle and the far post angle when the striker is
24 yards from the near post and 28 yards from the far post.
b) How far is the goalie from the ball?
c) To cover the near post, the goalie moves toward the near post in order
to make the near post angle and the far post angle equal. How far
toward her near post does the goalie need to move?

Answers

Where the following triangle problem is given, note that:

A) α [tex]\approx[/tex] 11.0

β  β [tex]\approx[/tex] 9.4


B) 25.59 yrds

C) 0.38 yrds

What is the explanation for the above?

A) To determine the near post angle and the far post angle when the striker is 24 yards from the near post

1/2 (24²) + 1/2 (28²) - 1/4(10²) = 655 (central line length formula)

Cos  α = (24² + 655 - 5²)/ (2 x 24 x √655)

= 0.98171498561

α = Cos ⁻¹ 0.98171498561

α = 10.973603643623608717848651724941

α [tex]\approx[/tex] 11.0° (Cosine Law)

For   28 yards from the far post.

Cos   β   = (28² + 655 - 5²)/ (2 x 28 x √655)

= 0.98659913977

 β  = Cos ⁻¹ 0.98659913977

 β  = 9.3905311636838307510867912796592

 β  [tex]\approx[/tex] 9.4°

B)  Distance between the goalie from the ball is

√655 = 25.592967784139454896443137575823

Distance  [tex]\approx[/tex] 25.59 yrds

C)  5-10 * ((24)/(24+28)) = 0.38 yrds (Angular Bisector Theorem)

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The polygon below is a regular polygon. Find the answer rounded to the nearest tenth.
HELP GIVING BRAINLIST HW DUE SOOON

Answers

Answer:

In a 30°-60°-90° right triangle, the length of the longer leg is √3 times the length of the shorter leg.

A = (1/2)Pa

= (1/2)(2)(8/√3)(6)(8)

= (384√3)/3 = 128√3 = 221.7 units^2

Find the total amount owed, to the nearest cent, for the following simple interest loans.

Answers

The total amount owed, to the nearest cent A = $ 3,283.44

What is simple interest?

Simple interest is interest that is only calculated on the initial sum (the "principal") borrowed or deposited. Generally, simple interest is set as a fixed percentage for the duration of a loan. No matter how often simple interest is calculated, it only applies to this original principal amount.

A = P + I where

P (principal) = $ 2,950.00

I (interest) = $ 333.44

A = P(1 + r/n)^nt

Where:

A = Accrued Amount (principal + interest)

P = Principal Amount

I = Interest Amount

R = Annual Nominal Interest Rate in percent

r = Annual Nominal Interest Rate as a decimal

r = R/100

t = Time Involved in years, 0.5 years is calculated as 6 months, etc.

n = number of compounding periods per unit t; at the END of each period

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Correct question:

Find the total amount owed, to the nearest cent, for a simple interest loan with a principal of $2950, an interest rate of 7.4% and a time period of 1.5 years. Show​

9999999999999999999999999999999999999999956596859873 -57854909049287634246299583729875472656475965593947699= ____________________________________________________________________98899876788877656687989/988998-*995895966++5966656566666666655555555555958545156548448489+4964898748/798784484878554659757564250216407694722=

Answers

Answer:

-4.7854909e+52

Step-by-step explanation:

how do i know

cuz i used a calculator

what evevn is your equation

Each marble bag sold by Eric’s Marble Company contains 3 red marbles for every 4 blue marbles. If a bag has 36 blue marbles, how many red marbles does it contain?

Answers

If 9x4=36 and there are 36 blue marbles, you just multiply 3 by 9 and you get 27 red marbles

Solve for x
x = 1+2+3+4..... Infinity

Answers

Answer:

x = -1/12

Step-by-step explanation:

It is actually a rather simple proof. Before we get to that, it’s important to understand a couple of other things. Let’s consider the following infinite summation:

X = 1 - 1 + 1 - 1 + 1 - 1 ...

Rearranging the above equation a little bit, we get:

X = 1 - (1 - 1 + 1 - 1 + 1 - 1 ...)

If you look at the term inside the brackets, it in fact equals X. So let’s substitute that:

X = 1 - X

2X = 1

X = 1/2

Now let’s consider another sum.

Y = 1 - 2 + 3 - 4 + 5 - ...

Writing it in another way, we get:

Y = 0 + 1 - 2 + 3 - 4 + 5 + ...

Adding the above two equations:

Y + Y = (1 - 2 + 3 - 4 + 5 ...) + (0 + 1 - 2 + 3 - 4 + 5 ...)

Grouping the corresponding terms within the brackets, we get:

2Y = 1 + 0 - 2 + 1 + 3 - 2 - 4 + 3 + 5 - 4 ...

2Y = 1 - (2-1) + (3-2) - (4-3) + ...

2Y = 1 - 1 + 1 - 1 + 1 - 1 ...

But the summation on the right hand side is X. Let’s substitute it:

2Y = X

2Y = 1/2

Y = 1/4

Finally, let’s consider our original question at hand i.e. the sum of all natural numbers:

S = 1 + 2 + 3 + 4 + ...

We defined Y earlier as:

Y = 1 - 2 + 3 - 4 + ...

Subtracting Y from S:

S - Y = 1 - 1 + 2 + 2 + 3 - 3 + 4 + 4 + ...

S - Y = 4 + 8 + 12 + 16 + ...

We just calculated the value of Y to be 1/4. So let’s substitute it:

S - 1/4 = 4 x (1 + 2 + 3 + 4 + ...)

S - 1/4 = 4S

3S = -1/4

S = -1/12

someone please help with finding the greatest common factor, my teacher didn't explain it well

Answers

The greatest common factor is 2z^2

How you find it is first you find the greatest common factor of the two numbers, which is 2 (2 is the greatest number that can be multiplied into 2 and 10; 2 times 1 = 2 and also 2 times 5 = 10)

Then you find the greatest common factor of the variables, which is z^2.

(z^2 is the largest that can go into z^3 and z^2 because z^2 times z = z^3 and z^2 = z^2)

After that, you just multiply them together to get 2z^2

Which two values are located at the same point on a number line? 4/1 and 4 , 1/3 and 3 , 8/8 and 8 , 6/2 and 4

Answers

The two values which are located at the same point on a number line as required to be determined are; 4/1 and 4.

Which answer choice represents equivalent points on the number line?

It follows from the task content that the answer choice which represents two values located at the same point on the number line be determined.

On this note, such two values must be equivalent.

Hence, by observation; the answer choice which represents two equivalent values is; 4/1 and 4 and they represent values located at the same point on the number line.

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Assume that when human resource managers are randomly​ selected, 49​% say job applicants should follow up within two weeks. If 7 human resource managers are randomly​ selected, find the probability that exactly 2 of them say job applicants should follow up within two weeks.

Answers

The probability that exactly 2 of them say job applicants should follow up within two weeks is 33.02%.

How to find the probability ?

We can use the binomial probability formula:

P(x) = C ( n, x ) × p ^ x × ( 1 - p ) ^ ( n - x )

Solving then gives:

P ( 2 ) = C ( 7, 2 ) x 0.49 ^ 2 x ( 1 - 0. 49 ) ^ ( 7 - 2)

P ( 2 )  = 21 x 0. 49 ^ 2 x ( 1 - 0. 49) ^5

=  21 x 0. 2401 x 0. 078109

=  0. 3302

In conclusion, the probability that 2 of the 7 human resource managers say job applicants should follow up within two weeks is approximately 0.3302 or 33.02%.

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The sector of a circle with a diameter of 8 feet has a central angle measure of 45°. What is the area of the sector?



A. π/2 ft²

B. π ft²

C. 2 π ft²

D. 8 π ft²

Answers

so, we know the diameter is 8, so that means its radius is half that, or 4.

[tex]\textit{area of a sector of a circle}\\\\ A=\cfrac{\theta \pi r^2}{360} ~~ \begin{cases} r=radius\\ \theta =\stackrel{degrees}{angle}\\[-0.5em] \hrulefill\\ r=4\\ \theta =45 \end{cases}\implies A=\cfrac{(45)\pi (4)^2}{360}\implies A=2\pi ~ft^2[/tex]

A surveyor whose eye level is 5 feet above the ground determines the angle of elevation to the top of an office building to be 41.7°. If the surveyor is standing 40 feet from the base of the building, what is the height of the building to the nearest foot?
A.) 32ft.
B)50 ft
C)36ft
D.)41ft​

Answers

The height of the building when the surveyor is standing that far is D.)41ft​

How to find the height of the building ?

The tangent function would be best to use to find the height because we would be able to use the adjacent and and opposite.

Assuming that 5 feet is the height and the angle of elevation is 41. 7 degrees, and the distance of 40 feet, we have :

tan ( A ) = (h - x) / D

tan ( 41. 7° ) = ( h - 5 ) / 40

h - 5 = 40 x tan ( 41. 7 ° )

h - 5 = 40 x 0.8895

h = 35.58 + 5

= 40.58

= 41 feet

The height of the building is 41 feet.

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Find the range for the set numbers

Answers

Answer:

25

Step-by-step explanation:

range = largest number - smallest number

38-13=25

Scott and Lana booked a cruise that departs from Seward, Alaska, but their flight flew into Anchorage, Alaska. The couple decided to travel from Anchorage to Seward on the Alaska Railroad's non-stop Coastal Classic route to enjoy the 117 miles of beautiful scenery. If the train had traveled 13 miles in 30 minutes, how long, in hours, was the non-stop train ride from Anchorage to Seward?
A. 4.5 hours
B. 18 hours
C. 3 hours
D. 9 hours

Answers

The answer is option A. That is, the time taken in hours if the train traveled 13 miles in 30 minutes is 4.5 hours.

What is the relation between distance travelled and time?

The relation between distance traveled and time is given by the formula:

Distance = Speed x Time

where distance is the total distance traveled, speed is the rate at which the distance is covered, and time is the duration for which the distance is covered. This formula applies to any type of motion, whether it is linear or circular, and it is often used to calculate the distance covered by an object given its speed and the time it traveled. Alternatively, the formula can also be used to calculate the time required to travel a certain distance given the speed at which the object is traveling.

Given that the total distance = 117 miles. We need to find the time taken in hours if the train traveled 13 miles in 30 minutes.

For that we can use the equation, distance = rate x time

Now, rate = distance/time

Distance = 13 miles, time = 30 minutes = 30/60 hours = 0.5 hours

Therefore, rate = 13 miles / 0.5 hours = 26 miles per hour

Now to find the time it took to travel the entire 117 miles:

time = distance/rate

time = 117 miles/ 26 miles per hour

time = 4.5 hours

Therefore, the answer is (A) 4.5 hours.

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Dr. Rollins is both an anthropologist and archeologist. While excavating some ruins in South America, he discovered a scale drawing of a replica of a Mayan pyramid.

-The scale for the drawing to the replica was 1 inch : 2 feet.
- The scale for the replica to the actual pyramid was 1 foot : 14 feet.

If the height of the pyramid on the drawing was 3 1/2 inches, what was the height of the actual pyramid?

A. 98 feet
B. 49 feet
C. 91 feet
D. 196 feet

Answers

Correct answer is option A. If the height of the pyramid on the drawing was 3 1/2 inches, then the height of the actual pyramid is 98 feet

How do we compare inches to feet comparison on a replica?

When a scale drawing or model is made, the actual object is typically much larger than the drawing or model. In order to represent the object in a smaller size, a ratio is used to scale down the dimensions. This ratio is can be in a fraction form or 'is to' form. We can use this ratio to easily calculate the dimensions of a replica from the actual object or vice versa.

To find the height of the actual pyramid, we need to use both scales given in the problem.

We can start by finding the height of the replica using the first scale:

1 inch on the drawing = 2 feet on the replica

So, 3.5 inches on the drawing = (3.5 * 2) feet on the replica = 7 feet on the replica

Now, using the second scale we can find the height of the actual pyramid:

1 foot on the replica = 14 feet on the actual pyramid

So, 7 feet on the replica = (7 * 14) feet on the actual pyramid = 98 feet

Therefore, the height of the actual pyramid is 98 feet.

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4. An opportunity cost that a business might face is
a. forgoing the interest that the owners could have earned on their savings if they had not
invested their savings in the business
Ob. forgoing rental income to be earned if the business rented out its building
forgoing the salaries the owners would have received at other jobs
OC.
c.
Od.
d. all of the above
5. The difference between macroeconomics and microeconomics is that
a. microeconomics studies inflation while macroeconomics studies taxes
Economics
b. macroeconomics looks at the economy as a whole while microeconomics looks at single
units in the economy
Oc. macroeconomics measures the price of a good and quantity demanded while
microeconomics looks
at things like unemployment or GDP
Od.
d. macroeconomics looks at single units in the economy while microeconomics looks at the
economy as a whole

Answers

4. The correct answer is a. Forgoing the interest that the owners could have earned on their savings if they had not invested their savings in the business. Opportunity cost refers to the cost of forgoing the next best alternative when making a decision. In this case, the opportunity cost of investing savings in a business is the interest that could have been earned if the savings were invested elsewhere.

5. The correct answer is b. Macroeconomics looks at the economy as a whole while microeconomics looks at single units in the economy. Macroeconomics is concerned with the overall performance of the economy, including issues such as inflation, unemployment, and economic growth. Microeconomics, on the other hand, focuses on individual units within the economy, such as households, firms, and markets.

help math will give brainlist

Answers

Answer:

arc PTR = 277°

Step-by-step explanation:

PS is the diameter of the circle , then arc PS = 180°

arc PTR = PS + SR = 180° + 97° = 277°

Answer:

arc PTR = 277°

Step-by-step explanation:

PS is the diameter of the circle , then arc PS = 180°

arc PTR = PS + SR = 180° + 97° = 277°

What is the value of x?

Answers

Answer:

12

Step-by-step explanation:

10x - 20 + 6x + 8 = 180

Supplementary angles

Answer:

x = 12

Step-by-step explanation:

The two given angles create a straight line (Definition of Straight Line). This means that:

[tex](10x - 20) + (6x + 8) = 180[/tex]

First, combine like terms. Like terms are terms that share the same amount of the same variables:

[tex](10x + 6x) + (8 - 20) = 180\\(16x) + (-12) = 180\\16x - 12 = 180\\[/tex]

Next, isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS.

PEMDAS is the order of operations and stands for:

Parenthesis

Exponents (& Roots)

Multiplications

Divisions

Additions

Subtractions

~

First, add 12 to both sides of the equation:

[tex]16x - 12 = 180\\16x - 12 (+12) = 180 (+12)\\16x = 180 + 12\\16x = 192[/tex]

Next, divide 16 from both sides of the equation:

[tex]\frac{16x}{16} = \frac{192}{16} \\x = \frac{192}{16}\\ x = 12[/tex]

12 is your answer.

~

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The box plot represents the scores on quizzes in a science class.

A box plot uses a number line from 74 to 86 with tick marks every one-half unit. The box extends from 77.5 to 81.5 on the number line. A line in the box is at 80. The lines outside the box end at 75 and 85. The graph is titled Science Quizzes, and the line is labeled Scores On Quizzes.

What value does 25% of the data lie above? Find the value.

Answers

81.5 because it’s the upper quartile which marks the 75% in the data.

the Ponde family's Powerjet pumps 420 gallons of water per hour. At this rate, how many gallons of water will it pump in 45 minutes?

Answers

the number of gallons of water it can pump inn 45 minutes is

How to determine the amount of water?

The given parameters that will help us to determine the quantity are

Powejet pumps 420 gallons of water per hour

how many gallons of water will it pump in 45 minutes  = ?

1 hour = 60 minutes

This means = 450/60  = 7 gallons

Therefore in  45 minutes it can pump 7*45 = 315 gollons

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NEED HELP WILL GIVE BRAINLIEST AND WILL RATE. Show work and I only need #1

Answers

The end behavior of f(x) is described as follows:

As x -> -∞, f(x) -> ∞.As x -> ∞, f(x) -> 0.

How to obtain the end behavior of a function?

The end behavior of a function is given by the limit of the function is the input x goes to either negative infinity or positive infinity.

The function for this problem is given as follows:

f(x) = 4(5/7)^x.

It is an exponential function with base with absolute value less than 1, hence the end behavior is given as follows:

Increases to the left of the graph -> As x -> -∞, f(x) -> ∞.Approaches the horizontal asymptote y = 0 at the right of the graph -> As x -> ∞, f(x) -> 0.

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Americans are stressed out!
A psychologist would like to estimate the proportion of Americans that say "the future of the nation is a
significant source of stress for me." To help form an estimate, the psychologist randomly selected 664
Americans and found that 69.6% of the sample agreed with the statement "the future of the nation is a
significant source of stress for me."
Using a 99% confidence level, determine the margin of error, E, and a confidence interval for the true
proportion of all Americans that say the "the future of the nation is a significant source of stress for me."
Report the confidence interval using interval notation. Round solutions to four decimal places, if necessary.




The margin of error is given by E:

A 99% confidence interval is given by:

Answers

To find the margin of error, we can use the formula: E = z√((p(1-p))/n)

How is margin of error determined?

where z is the z-score for a 99% confidence level, p is the sample proportion, and n is the sample size.

From the table of standard normal distribution, the z-score for a 99% confidence level is 2.576.

Plugging in the values, we get:

E = 2.576√((0.696(1-0.696))/664) ≈ 0.0385

So the margin of error is 0.0385.

To find the confidence interval, we can use the formula:

p ± E

where p is the sample proportion and E is the margin of error.

Plugging in the values, we get:

0.696 ± 0.0385

So the 99% confidence interval for the true proportion of all Americans that say "the future of the nation is a significant source of stress for me" is (0.6575, 0.7345). In interval notation, this can be written as [0.6575, 0.7345].

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Evaluate the function as indicated

[tex]g(x) = {5.9}^{x} [/tex]

(a) x = -1 G(-1) =
(b) G(-2) = x = -2
(c) x = √5 G(√5) =

what is the answer for a, b, and c?

Answers

a. The answer is G(-1) = -4.
b. The answer is G(-2) = 1.
c. The answer is G(√5) = 2 + √5.

find the values of variables then find the lengths of the sides of each quadrilateral ​

Answers

4 , 7 , 2 are the values of variables then find the lengths of the sides of each quadrilateral ​.

What do math quadrilaterals mean?

Four sides, four vertices, and four angles make up a quadrilateral, which is a two-dimensional form. Concave and convex are the two most common forms. The vertices on them total four. The sides of them are four. 360 degrees is the total number of interior angles.

                                   There are two diagonals between them. A polygon having four sides is referred to as a quadrilateral. A line segment whose endpoints are the opposing vertices of a quadrilateral is said to be the diagonal of the quadrilateral.

2X + 2 = 4

   2X = 4 -2

      2X = 2

        X = 1

2x + 2 = 2 * 1 + 2  = 4

4x + 3 = 4 * 1 + 3 = 7

2x = 2 * 1 = 2

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4 , 7 , 2 are the values of variables then find the lengths of the sides of each quadrilateral ​.

What do math quadrilaterals mean?

Four sides, four vertices, and four angles make up a quadrilateral, which is a two-dimensional form. Concave and convex are the two most common forms. The vertices on them total four. The sides of them are four. 360 degrees is the total number of interior angles.

                                   There are two diagonals between them. A polygon having four sides is referred to as a quadrilateral. A line segment whose endpoints are the opposing vertices of a quadrilateral is said to be the diagonal of the quadrilateral.

2X + 2 = 4

   2X = 4 -2

      2X = 2

        X = 1

2x + 2 = 2 * 1 + 2  = 4

4x + 3 = 4 * 1 + 3 = 7

2x = 2 * 1 = 2

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Gary and Ann have a joint checking account their bounce at the beginning of October was 9145.87 during the month they made deposits totalling 2,783.71 wrote checks totaling 4,871.90 paid a maintenance fee of $12 earned 11.15 at interest on the account what was the balance at the end of the month?

Answers

The balance at the end of the month was $7046.93.

What is balance at the end of the month?

To determine the balance at the end of the month, we need to:

add the initial balance to the deposits and interest earnedsubtract the checks written and fees paid.

Data

Starting balance = $9145.87

Deposits = $2783.71

Interest earned = $11.15

Checks written = $4871.90

Maintenance fee = $12

Balance at the end of the month will be:

= Starting balance + Deposits + Interest earned - Checks written - Maintenance fee

= $9145.87 + $2783.71 + $11.15 - $4871.90 - $12

= $7046.93.

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what is the answer to this problem

Answers

47/40 as a fraction or 1 7/40 as a mixed number

Edward and Diana walked to the dock at 2 miles per hour, jumped into the boat, and motored to Dillion at 10 miles per hour. If the total distance was 12 miles and the trip took 5 hours in all, how far did they go by boat?

Answers

The distance for boat is,

=  43.2 miles

Given that;

Edward and Diana walked to the dock at 2 miles per hour, jumped into the boat, and motored to Dillion at 10 miles per hour

Now, For Walk DATA:

Rate = 2 mph ; time = x hrs.

Then, distance = 2x miles

For Boat DATA:

Rate = 10 mph ; time = 5 - x hrs

Then, distance = 10 (5 - x) miles

Hence, We can formulate;

distance + distance = 12 miles

2x + 10 (5 - x) = 20

2x + 50 - 10x = 20

30 = 8x

x = 3.6

Hence, Boat time ,

5 - x = 5 - 3.6 = 1.4 hr (boat time)

And, The value of Boat distance = 12x = 12 x 3.6 = 43.2 miles

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Sarah has a coupon for an oil change with synthetic oil for $49.95. She can buy 5 quarts of synthetic oil, which is what her car needs, for $37.54 and an oil filter for $9.47. How much can she save by doing the oil change herself?

Answers

Step-by-step explanation:

If Sarah buys the oil and oil filter separately, she would spend:

Cost of oil = $37.54

Cost of oil filter = $9.47

Total cost = $37.54 + $9.47 = $47.01

Therefore, Sarah can save:

Coupon price - Total cost = $49.95 - $47.01 = $2.94

So, Sarah can save $2.94 by doing the oil change herself instead of using the coupon.

What is the value of x in both these questions

Answers

Answer:

x + 5 + 7x - 5 + x = 180

9x = 180

x = 20

So the measure of angle M is x + 5 = 20 + 5 = 25°

using cramer rao lower bound method, with a random sample of size n, find a minimum variance unbiased estimator of the parameter,λ of a poisson population

Answers

The minimum variance unbiased estimator of the parameter,λ of a poisson population is λ = Σxi/n.

What is variance?

Variance is a measure of how spread out a set of data is. In statistics, it is the average of the squared differences from the mean of a set of values. It is calculated by taking the sum of the squared deviations from the mean and dividing it by the number of data points.

According to given information:

Let X1, X2, ..., Xn be a random sample from a Poisson distribution with mean λ. The likelihood function is given by:

[tex]L(\lambda | x) = \pi[e^{(-\lambda)} \lambda^{(xi)} / xi!][/tex]

Taking the natural logarithm and differentiating with respect to λ:

ln L(λ | x) = -nλ + ln(λ) Σxi - Σln(xi!)

d/dλ ln L(λ | x) = -n + Σxi/λ

Setting the derivative equal to zero and solving for λ, we get:

λ = Σxi/n

This is the sample mean of the Poisson distribution, which is an unbiased estimator of λ. Moreover, using the Cramer-Rao lower bound, we can show that it is also the minimum variance unbiased estimator of λ.

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The mean weight of an adult is 70 kilograms with a standard deviation of 8 kilograms.

If 87 adults are randomly selected, what is the probability that the sample mean would be greater than 70.8 kilograms? Round your answer to four decimal places.

Answers

The probability that the sample mean would be greater than 70.8 kilograms is given as follows:

0.1762 = 17.62%.

How to obtain probabilities using the normal distribution?

The z-score of a measure X of a normally distributed variable that has mean represented by [tex]\mu[/tex] and standard deviation represented by [tex]\sigma[/tex] is obtained by the equation presented as follows:

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

The z-score represents how many standard deviations the measure X is above or below the mean of the distribution of the data-set, depending if the obtained z-score is positive(above the mean) or negative(below the mean).The z-score table is used to obtain the p-value of the z-score, and it represents the percentile of the measure X in the distribution.By the Central Limit Theorem, the sampling distribution of sample means of size n has standard deviation given by the equation presented as follows: [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

The parameters for this problem are given as follows:

[tex]\mu = 70, \sigma = 8, n = 87, s = \frac{8}{\sqrt{87}} = 0.8577[/tex]

The probability is one subtracted by the p-value of Z when X = 70.8, hence:

Z = (70.8 - 70)/0.8577

Z = 0.93

Z = 0.93 has a p-value of 0.8238

1 - 0.8238 = 0.1762.

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