[tex] \displaystyle \rm \sum_{n = 0}^ \infty \frac{(n! {)}^{2} }{(2n + 1)!} [/tex]​

Answers

Answer 1

Observe that

[tex]\dfrac{(n!)^2}{(2n+1)!} = \dfrac{n!(2n-n)!}{(2n+1)(2n)!} = \dfrac1{(2n+1)\binom{2n}n}[/tex]

Starting with a well-known series

[tex]\displaystyle 2\arcsin^2(x) = \sum_{n=1}^\infty \frac{(2x)^{2n}}{n^2 \binom{2n}n}[/tex]

we take some (anti)derivatives to find a sum that more closely resembles ours.

Let [tex]f(x)=2\arcsin^2(x)[/tex]. Then

[tex]\displaystyle f'(x) = 2 \sum_{n=1}^\infty \frac{2^{2n} x^{2n-1}}{n \binom{2n}n}[/tex]

[tex]\displaystyle x f'(x) = 2 \sum_{n=1}^\infty \frac{2^{2n} x^{2n}}{n \binom{2n}n}[/tex]

[tex]\displaystyle x f''(x) + f'(x) = 4 \sum_{n=1}^\infty \frac{2^{2n} x^{2n-1}}{\binom{2n}n}[/tex]

[tex]\displaystyle x^2 f''(x) + x f'(x) = 4 \sum_{n=1}^\infty \frac{2^{2n} x^{2n}}{\binom{2n}n}[/tex]

Noting that both sides go to zero as [tex]x\to0[/tex], by the fundamental theorem of calculus we have

[tex]\displaystyle \sum_{n=1}^\infty \frac{2^{2n} x^{2n+1}}{(2n+1)\binom{2n}n} = \frac14 \int_0^x (t^2 f''(t) + t{}f'(t)) \, dt[/tex]

so that when [tex]x=\frac12[/tex], and rearranging some factors and introducing a constant, we recover a useful sum.

[tex]\displaystyle \sum_{n=0}^\infty \frac1{(2n+1)\binom{2n}n} = 1 + \frac12 \int_0^{1/2} (x^2 f''(x) + x f'(x)) \, dt[/tex]

Integrate by parts.

[tex]\displaystyle \int_0^{1/2} x^2 f''(x) \, dx = \frac14 f'\left(\frac12\right) - 2 \int_0^{1/2} x f'(x) \, dx[/tex]

[tex]\displaystyle \int_0^{1/2} x f'(x) \, dx = \frac12 f\left(\frac12\right) - \int_0^{1/2} f(x) \, dx[/tex]

Then our sum is equivalent to

[tex]\displaystyle \sum_{n=0}^\infty \frac1{(2n+1)\binom{2n}n} = 1 + \frac18 f'\left(\frac12\right) - \frac14 f\left(\frac12\right) + \int_0^{1/2} \arcsin^2(x) \, dx[/tex]

The remaining integral is fairly simple. Substitute and integrate by parts.

[tex]\displaystyle \int_0^{1/2} \arcsin^2(x) \, dx = \int_0^{\pi/6} u^2 \cos(u) \, du \\\\ ~~~~~~~~~~~~~~~~~~~~~~~~~ = \frac{\pi^2}{72} - 2 \int_0^{\pi/6} u \sin(u) \, du \\\\ ~~~~~~~~~~~~~~~~~~~~~~~~~ = \frac{\pi^2}{72} + \frac\pi{2\sqrt3} - 2 \int_0^{\pi/6} \cos(u) \, du \\\\ ~~~~~~~~~~~~~~~~~~~~~~~~~ = \frac{\pi^2}{72} + \frac\pi{2\sqrt3} - 1[/tex]

Together with

[tex]f\left(\dfrac12\right) = 2 \arcsin^2\left(\dfrac12\right) = \dfrac{\pi^2}{18}[/tex]

[tex]f'\left(\dfrac12\right) = \dfrac{4\arcsin\left(\frac12\right)}{\sqrt{1-\frac1{2^2}}} = \dfrac{4\pi}{3\sqrt3}[/tex]

we conclude that

[tex]\displaystyle \sum_{n=0}^\infty \frac{(n!)^2}{(2n+1)!} = \sum_{n=0}^\infty \frac1{(2n+1)\binom{2n}n} \\\\ ~~~~~~~~~~~~~~~~~~ = 1 + \left(\frac18\cdot\frac{4\pi}{3\sqrt3}\right) - \left(\frac14\cdot\frac{\pi^2}{18}\right) + \left(\frac{\pi^2}{72} + \frac\pi{2\sqrt3} - 1\right) \\\\ ~~~~~~~~~~~~~~~~~~ = \boxed{\frac{2\pi}{3\sqrt3}}[/tex]


Related Questions

If a person who works 40 hours per week earns 51,200 per year, estimate that person’s hourly wage by rounding the annual income to the nearest ten thousand. Use the estimated that there are 50 weeks in a year

Answers

Answer:

$20 an hour

Step-by-step explanation:

20 x 50 = 1,000 and 1,000 x 51 = 51,000



Riley has $200.00. She spends $60.00 on a video game.
What percent of her money does Riley spend? Draw a diagram to show your thinking.

Answers

Answer:

Step-by-step explanation:

PLEASEEE HELLPPPP


Mr. Lee is retiling his pantry floor. His pantry measures 4½ feet by 6½ feet. Each tile he plans to use measures ½ foot by ½ foot.​

Answers

Answer:

117 tiles

Step-by-step explanation:

Area of rectangle = length * width

To find the number of tiles divide the area of pantry floor by the area of a tile.

Convert mixed fraction to improper fraction.

[tex]\sf 4\dfrac{1}{2}=\dfrac{9}{2}\\\\\\6\dfrac{1}{2}=\dfrac{13}{2}[/tex]

  [tex]\sf \boxed{\text{\bf Number of tiles = $\dfrac{Area \ of \ floor}{area \ of \ a \ tile}$}}[/tex]

                                 [tex]\sf = \left(\dfrac{9}{2}*\dfrac{13}{2}\right ) \ \div \left(\dfrac{1}{2}*\dfrac{1}{2}\right)\\\\\\= \left(\dfrac{117}{4}\right) \ \div \left(\dfrac{1}{4}\right)\\\\\\[/tex]

Use KCF method.

Keep the first fraction.Change division to multiplication.Flip the second fraction.

                                   [tex]\sf =\dfrac{117}{4}*\dfrac{4}{1}\\\\= 117[/tex]

Write the expression in words 25+24 divide 6

Answers

The expression in words 25+24 divide 6 will be the addition of 25 and 24 divided by 6.

How to illustrate the information?

It should be noted that an expression simply shows the relationship that exists between the variables.

In this case + means addition.

Therefore, the expression in words 25+24 divide 6 will be the addition of 25 and 24 divided by 6.

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The table shows the results of a survey of male and female students about whether their school should adopt a dress code. What is the probability that a randomly selected male student says that the school should adopt a dress code? Give your answer as a decimal rounded to the nearest thousandths

Answers

Using it's concept, there is a 0.462 probability that a randomly selected male student says that the school should adopt a dress code.

What is a probability?

A probability is given by the number of desired outcomes divided by the number of total outcomes.

From the table, we have that:

There are 30 + 35 = 65 male students.30 say that the school should adopt a dress code.

Hence the probability is given by:

p = 30/65 = 0.462.

0.462 probability that a randomly selected male student says that the school should adopt a dress code.

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In the adjoining figure, AB//CD. Show that, AC//BD.
Learn
for

A
70°
C
50%
B
60%D
T

Answers

As shown in the next figure, AB/CD results in AC/BD.

The definition of alternating interior angle

When a transversal connects two coplanar lines, alternate interior angles are created. They are located on the transverse sides of the parallel lines, but on the inner side of the parallel lines.

based on the given value;

we are aware of this;

The adjacent figure displays

AB//CD.

∠BCD=∠ABC=50

(By alternating interior angle are equal)

∠ACB=70

∠ACD=∠BCD+∠ACB

          =50+70

          =120

∠CDB=60

∠ACD+∠CDB=180

Hence; AC//BD

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An employee at Kennedy Space Center (KSC) lives in Daytona Beach and works in the vehicle assembly building (VAB). She
carpools to work with a colleague. She drives 7 miles from her house to the park-and-ride. Then she rides with her colleague from the
park-and-ride in Daytona Beach to the KSC headquarters building, and then takes the KSC shuttle from the headquarters building to
the VAB. The drive from the park-and-ride to the headquarters building is of her total trip, and the shuttle ride is of her total trip.
How many miles does she travel from her house to the VAB on days her colleague drives?

Answers

Using proportions, it is found that she travels 60 miles from her house to the VAB on days her colleague drives.

What is the missing information?

The drive from the park-and-ride to the headquarters is 5/6 of her trip.The shuttle ride is 1/20 of her trip.

What is a proportion?

A proportion is a fraction of a total amount, and the measures are related using a rule of three. Due to this, relations between variables, either direct(when both increase or both decrease) or inverse proportional(when one increases and the other decreases, or vice versa), can be built to find the desired measures in the problem, or equations to find these measures.

The first step is finding the fraction corresponding to the 7 miles, hence considering that the total is of 100% = 1 and the fractions given above, we have that:

1 - 5/6 - 1/20 = 1 - 0.8333 - 0.05 = 0.1167.

The 7 miles represent 0.1167 of the trip, hence:

0.1167x = 7

x = 7/0.1167

x = 60.

She travels 60 miles from her house to the VAB on days her colleague drives.

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What would be the area of a triangle with a base of 16 inches and a height of 1/8 inch?


Answers

Answer:

1 in^2

Step-by-step explanation:

Area of triangle = 1/2 x base x height.
Area = 1/2 x 16 x 1/8
Area = 8 x 1/8
Area = 1 square inch

If f(x) = x
What is g(x) if the graph moves 9 units up and 2 units to the right

Answers

Shift 2 units left:  y = [tex](x+2)^{2}[/tex]

shift up 9 units:  y =  [tex](x+2)^{2}[/tex]  + 9

reflect in the x-axis:  y = -  [tex](x+2)^{2}[/tex] - 9

y =[tex]x^{2}[/tex]

Shift 2 units left:  y = [tex](x+2)^{2}[/tex]

Then, shift up 9 units:  y =  [tex](x+2)^{2}[/tex]  + 9

Then, reflect in the x-axis:  y = -  [tex](x+2)^{2}[/tex] - 9

Each reference coordinate line is referred to as an axis of the system, or simply an axis (plural axes),  and its origin is at the ordered pair intersection (0, 0). The positions of the perpendicular projections of the point onto the two axes, represented as signed distances from the origin, can likewise be used to establish the coordinates.

The same idea may be used to determine the location of any point in three dimensions using three Cartesian coordinates.

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What is the Area of the Figure?

Answers

Check out the attached photo
The area of the figure is 58ft squared

A fair die is rolled four times what is the probability that a four is obtained on at least one of the rolls

Answers

The probability that a four is obtained on at least one of the rolls 51.71 %.

We need to use this formula in order to find out the probability of getting 4

1 – 54/64

=1 -  625/1296

=  671/1296

= 51.71%

Hence , the probability that a four is obtained is  51.71 %.

A traditional die is a cube with each of its six faces marked with a different number of dots from 1 to 6. Probability is the branch of mathematics concerning numerical descriptions of how likely an event is to occur, or how likely it is that proportion is true. The probability of an event is a number between 0 and 1 , where roughly speaking , 0 indicated impossibility of the event and 1 indicates certainty.

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A cannonball is fired in the air at an angle of 45∘. How far does it travel before it is
1,700 feet above ground? (Assume the cannonball travels in a straight line. Ignore the force of gravity and wind resistance. Give your answer to the nearest foot.)

Answers

It travels 2404 feet before it is 1,700 feet above ground;

The given question can be represented in the form of equation;          

y = tan(45°)x + c;

Since it is launched from ground; c = 0;

thus; y = x is the equation of motion of cannonball;

According to question;  y = 1700 feet

x = 1700 feet;

The distance travelled by cannonball will be

√(x² + y² = √(1700² + 1700²)                         (∵ it is a right angled triangle;

                                                                           using Pythagoras theorem)              

               = 2404.16 feet

              ≅ 2404 feet

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Mathematics, 26.09.2021 14:00, aliyahgregory
Point Q is the midpoint of segment PR. QR = 18 and PR = 5x+6.

Answers

we get the value of x as 2.4 units when QR is 18 units.

We are given a segment PR.

We are also given that Q is the mid point of the segment.

So, we get that

PQ = QR

Now, we have that

QR = 18 units

PR = 5 x + 6

We have to sind the value of x.

Substituting the values of PR and QR in the equation, we get that:

5 x + 6 = 18

5 x = 18 - 6

5 x = 12

x = 12 / 5

x = 2.4 units

Therefore, we get the value of x as 2.4 units when QR is 18 units.

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At a carnival, Jenny bought 7 packs of 13 tickets each. She has used 39 of the tickets so far. How many tickets does she have left?

Answers

Answer:

52 tickets

Step-by-step explanation:

7 x 13 = 91

91 - 39 = 52

What is the value of x in the equation 1/5x - 2/3y =30, when y = 15

Answers

Answer:

x = 200

Step-by-step explanation:

1/5x - 2/3y = 30 when y = 15

     2/3 * 15 = 10

1/5x - 10 = 30

1/5x = 40

x = 200

Answer:

x = 200

Step-by-step explanation:

=>  [tex]\frac{1}{5}x-\frac{2}{3}y=30[/tex]

=> Put the value of y into the equation

=> [tex]\frac{1}{5}x-\frac{2}{3}*15=30[/tex]

=> Simplify

=> [tex]\frac{1}{5}x-10=30[/tex]

=> Shift the 10 to the right side

=> [tex]\frac{1}{5}x=40[/tex]

=> Solve For x

=> [tex]x = 200[/tex]

- If The Answer Helped You Please Mark As Brainliest

Work out the missing number in this sum:
6.802 6 + 0.8+___

Answers

Answer: The answer might be 0.002

Step-by-step explanation: Looking at the number made it look like it.

and pls brainliest if I am right

3 consecutive numbers have a sum of 120. Write an equation to
determine what numbers these are, and find them.

Answers

Let x equal the first number then (x+1) equals the next number and (x+2) is the last

120 = x + (x+1) + (x+2)
120 = 3x + 3
117 = 3x
x = 39

The numbers are 39, 40, and 41

PLEASE HELP


8√18 x 3√8 =

Answers

Answer:

hope this helps

Step-by-step explanation:

A store scale measures the weight of objects within 0.4 ounce of the actual weight. The store scale measured an object with an actual weight of x ounces, displaying 7.2 ounces on its screen. Which expression, using absolute value, shows the distance the actual weight is from the weight shown on the scale?

Hurry please!!​

Answers

The distance the actual weight is from the weight shown on the scale is

l x - 7.2 l

In the given statement is :

A store scale measures the weight of objects within 0.4 ounce of the actual weight. The store scale measured an object with an actual weight of x ounces, displaying 7.2 ounces on its screen.

And, Which expression, using absolute value, shows the distance the actual weight is from the weight shown on the scale

Now, Let's start the solution:

A store scale measuring an object with an actual weight = x ounces

and, displaying the weight on its screen is = 7.2 ounces

By using the absolute value

Hence, The distance the actual weight is from the weight shown on the scale is l x - 7.2 l

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50 pounds of pet food for $37.99? what is the unit rate?

Answers

Answer: 1.31613582522

Step-by-step explanation:

The formula for calculating commission is

A c=x-y

B c=y-x

C c=mx+b

D c=prn

Answers

Your answer is D. (C=PRN)


Find two numbers a and b whose sum a + b is -9 and whose difference a - b is -1.

Answers

Answer:

a has two solutions for this case.

a₁: [tex]a=-9-b[/tex]

a₂: [tex]a=-1+b[/tex]

Step-by-step explanation:

A1

         [tex]a+b-b=-9-b\\a=-9-b[/tex]

A2

         [tex]a-b+b=-1+b\\a=-1+b[/tex]

➲ I hope this helps you.


During a war, allies sent food and medical kits to help survivors. Each food kit helped 8 people and each medicine kit helped 6 people. Each plane could carry no more than 80,000
food kit weighed 20 pounds and each medicine kit weighed 10 pounds. In addition to the weight constraint on its cargo, each plane could carry a total volume of supplies that did no
cubic feet. Each food kit was 1 cubic foot and each medical kit also had a volume of 1 cubic foot. Assume that those helped by medicine kits were not helped by the food kits and vi
was the maximum number of people that could be helped with one plane of supplies?

Answers

Using a system of equations, it is found that the maximum number of people that could be helped with one plane of supplies is: 40,000.

What is a system of equations?

A system of equations is when multiple variables are related, and equations are built to find the values of each variable, according to the relations given in the problem.

For this problem, the variables are given as follows, considering the situation described:

Variable x: number of food kits sent.Variable y: number of medicine kits sent.

Each food kit helped 8 people and each medicine kit helped 6 people, hence the total number of people helped is given by:

T = 8x + 6y.

This is because we consider that people were helped by only one of them, never both.

Each plane could carry no more than 80,000 pounds. Each food kit weighed 20 pounds and each medicine kit weighed 10 pounds, hence:

20x + 10y = 80000

2x + y = 8000

y = 8000 - 2x.

The maximum volume is of 6000 cubic feet, hence:

x + y = 6000.

y = 6000 - x.

Equaling both equations:

8000 - 2x = 6000 - x

x = 2000.

y = 6000 - x = 4000.

Then the maximum number of people helped is:

T = 8x + 6y = 8 x 2000 + 6 x 4000 = 40,000.

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The quotients of 16.5 divided by 10

Answers

I believe the answer is 1.65

Question 27 help pls

Answers

Using a system of equations, it is found that you should mix 7 pounds of dried fruit and 3 pounds of nut.

What is a system of equations?

A system of equations is when two or more variables are related, and equations are built to find the values of each variable.

For this problem, the variables are given as follows:

Variable x: Number of pounds of dried fruit mix.Variable y: Number of pounds of nut mix.

The mixture has a total of 10 pounds, hence:

x + y = 10 -> y = 10 - x -> x = 10 - y.

Considering the cost per pound of each, and the total cost of 10 x 5.34 = $53.4, we have that:

4.5x + 7.3y = 53.4.

Replacing x = 10 - y, we have that:

4.5(10 - y) + 7.3y = 53.4.

2.8y = 8.4.

y = 8.4/2.8

y = 3.

x = 10 - 3 = 7.

You should mix 7 pounds of dried fruit and 3 pounds of nut.

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How to find A and B?

Answers

Answer:more work pls

Step-by-step explanation:

Can somebody help me if you know what this is

Answers

Answer:

C

Step-by-step explanation:

this question is horribly phrased.

as far as I can tell after reading this multiple times, this is again looking for the GCF : the greatest common factor.

so, again, prime factor analysis :

168 :

168 ÷ 2 = 84

84 ÷ 2 = 42

42 ÷ 2 = 21

21 ÷ 2 no

21 ÷ 3 = 7

7 ÷ 3 no

7 ÷ 5 no

7 ÷ 7 = 1 finished

168 = 2³×3×7

120 :

120 ÷ 2 = 60

60 ÷ 2 = 30

30 ÷ 2 = 15

15 ÷ 2 no

15 ÷ 3 = 5

5 ÷ 3 no

5 ÷ 5 = 1 finished

120 = 2³×3×5

the GCF is the part of the prime factors both numbers share :

2³×3 = 8×3 = 24

so, they can make 24 fruit cups with identical content and using all the fruits.

these pieces of information were missing in the text.

based on the text without the answer options I was already going for the maximum that each fruit cup has one piece of fruit, and that gives us 168 + 120 = 288 fruit cups max.

The area of a parallelogram is 10 square inches. What is the missing measurement?​

Answers

Answer:

nose ....................

4cm is the new character because without it it wouldn’t be complete

A school club consists of 26 male students and 11 female students. If 4 students are selected to represent the club in the student government, what is the probability 2 will be male and 2 will be female?

Answers

The probability of selecting two male students is 0.47

The probability of selecting two female students is 0.08

Given,

Number of male students in a school club = 26

Number of female students in a school club = 11

Total number of students in the club = 26 + 11 = 37

Number of students selected to represent the club in the student government = 4

We have to find the probability of selecting 2 male and 2 female students:

Then,

The probability of selecting two male students = (26 / 37) × (25 / 37) = 0.47

The probability of selecting two female students = (11 / 37) × (10 / 37) = 0.08

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Which expression can be used to convert 100 USD to Japanese yen?

Answers

Answer:

The expression that would be most useful in converting $100 to Japanese Yen is 100 ( 99.30487 Yen / 1)

You can use direct proportion to solve this:

If $1 is to Y99.30487 then what will $100 be equal to:

1         :          99.30487 Yen

100    :                x

Cross multiply to get:

1x = 99.30487 Yen x 100

x = (99.30487 Yen x 100) / 1

Which can be written as:

= 100 ( 99.30487 Yen / 1)

In conclusion, the most useful expression to convert $100 to Yen is 100 (99.30487 Yen / 1)

Step-by-step explanation:

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