Find the sum S below:
[tex] \displaystyle \large{S = \frac{2}{1 \cdot 3} + \frac{2}{3 \cdot 5} + \frac{2}{5 \cdot 7} + ... + \frac{2}{(2n - 1)(2n + 1)} }[/tex]
Please show your work too. Thanks!​

Answers

Answer 1

You can use the same technique I showed in another one of your questions (24467305).

Partial fractions:

[tex]\dfrac2{(2n-1)(2n+1)} = \dfrac a{2n-1} + \dfrac b{2n+1} \\\\ \implies 2 = a(2n+1) + b(2n-1) = (2a+2b)n + a- b \\\\ \implies \begin{cases}2a+2b=0 \\ a-b = 2\end{cases} \implies a = 1, b=-1[/tex]

Then we have a telescoping sum,

[tex]S = \displaystyle \sum_{k=1}^n \frac 2{(2k-1)(2k+1)} \\\\ S = \sum_{k=1}^n \left(\frac1{2k-1} - \frac1{2k+1}\right) \\\\ S = 1-\frac13 + \frac13 - \frac15 + \cdots +\frac1{2n-3}-\frac1{2n-1}+\frac1{2n-1}-\frac1{2n+1} \\\\ S = 1 - \frac1{2n+1} = \boxed{\frac{2n}{2n+1}}[/tex]

(And in case you were actually interested in an infinite sum, we can see that this converges to 1 as n goes to ∞.)


Related Questions

A car is traveling 90 miles per hour. How fast is it traveling in miles per minute?​

Answers

Answer: 1.5 miles per minute

Step-by-step explanation:

The ratio for the hours is 90 Miles : 60 Minutes

Since 1 hour is 60 minutes, then 1 minute is 1/60 of a hour.

So, 1/60 will be the constant.

[tex]\frac{90}{1/60}[/tex]=1.5

One bulb of elephant garlic costs $2. How
many bulbs of elephant garlic can you buy for
$20?

Answers

Answer:

You can buy 10 bulbs of elephant garlic

Step-by-step explanation:

Since each bulb of elephant garlic is 2.

1 x 2 = $2

That is the cost of 1 elephant garlic.

10 x 2 = $20

That is the cost of 10 elephant garlic.

Find the area of the rectangle with the given base and height.
13 ft, 2 in

Answers

Answer:

Area of rectangle =  2.16 [tex]ft^{2}[/tex]

Step-by-step explanation:

Given ,

Base = 13 ft = 156 in

Height = 2 in

Area of rectangle = base * height

area =  156 * 2

area = 312 [tex]in^{2}[/tex]

area in square foot = [tex]\frac{312}{144}[/tex] = 2.16 [tex]ft^{2}[/tex] approx

             

pls answer this i need help

Answers

Answer:

Step-by-step explanation:

a) Number = x

Multiply it by 3 = 3*x = 3x

Now add 4 to it: 3x + 4

Equation:  

3x +4 = 22

b)

3x + 4 = 22

Subtract 4 from both sides

3x + 4 -4 = 22 - 4

        3x = 18

Divide both sides by 3

3x/3 = 18/3

x = 6

Answer:

Below in bold.

Step-by-step explanation:

The equation is

3x + 4 = 22

3x = 22 - 4 = 18

x = 18/3

x = 6.

Find the least number which must be subtracted from each of the following numbers
so as to get a perfect square. Also find the square root of the perfect square so
obtained.
(i) 402 (ii) 1989 (iii) 3250 (iv) 825
(v) 4000

Answers

Step-by-step explanation:

1 ) 402

402 - 2 = 400 which is a perfect sqrt ( 20)^2

so u must subtract 2

2) 1989

1989 - 53 = 1936 which is a perfect sqrt (44)^2

3) 3250

3250 -1 = 3249 which is a prefect sqrt (57)^2

4) 4000

4000 - 31 = 3969 which is a perfect sqrt (63)^2

anyone solve this maths questions from integers​

Answers

Answer:

See THE IMAGE FOR SOLUTION

Answer:

3) Verify the following: (a) 48 = 48, TRUE (b) 230 = 230, TRUE

Step-by-step explanation:

3) Verify the following:

a. 16 [7 + (-4)] = [16 × 7] + [16 × (-4)]

= 16 [7 -4] = [112] + [16 × -4]

= 16 [3] = [112] + [-64]

= 48 = 112 - 64

= 48 = 48        

This is true because both sides are equal.

b. -23 × [(-8) + (-2)] = [(-23) × (-8)] + [(-23) × (-2)]

= -23 × [-8 - 2] = [-23 × -8] + [-23 × -2]

= -23 × [-10] = [184] + [46]

= -23 × -10 = 184 + 46

= 230 = 230

This is true because both sides are equal.

how do you found the difference from -5 - (-3) = ?

Answers

Answer:

-2

Step-by-step explanation:

-5 - (-3)

-5 + 3

= -2

ANSWER: -2

-5 - (-3)
-5 + 3
-2

Solve the equation.
X-6= 8
A x=-2
B x=2
C x=-14
D x= 14

Answers

Answer:

Option D is correct

Step-by-step explanation:

[tex]x - 6 = 8 \\ x = 8 + 6 \\ x = 14[/tex]

Hope it is helpful....

Answer:

Option D is correct

Step-by-step explanation:

[tex]x - 6 = 8 \\ x = 8 + 6 \\ x = 14[/tex]

Hope it is helpful.....

i need help with numbers 15 and 18!!! what does x equal? help asap!!

Answers

Answer:

15. x = 112 degrees

18. x = 120 degrees

Step-by-step explanation:

15.

A triangle's angles always equal 180 degrees so we can find the two unknown angles by subtracting 44 from 180 and then dividing it by 2.

2a + 44 = 180

2a = 136

a = 68

Each unknown angle equals 68 degrees. The line from 44 degrees to x degrees segments a line that has a 180 degree angle so we can subtract 68 from 180 to get x.

x + 68 = 180

x = 112

18.

We can use the same concept here but now every angle equals each other so we can divide 180 by 3 to get the measure of those angles.

3a = 180

a = 60

Now we do the same thing as last time to find x.

x + 60 = 180

x = 120

Riley's monthly bank statement showed the following deposits and withdrawals:
-−$105.11, -−$33.75, $113.62, $119.42, $29.64
If Riley's balance in the account was $35.27 at the beginning of the month, what was the account balance at the end of the month?

Answers

Answer:

$159.09

Step-by-step explanation:

Math

Select the point that is a solution to the system of inequalities.
ys-X+3
ys x2-3x

Answers

Answer:

B (-1 , 0)

Step-by-step explanation:

0 <= -(-1) +3

0 <= 4

0 <= (-1)^2 - 3 (-1)

0<= 4

I need Ans Fast !!!!!!!

Answers

Step-by-step explanation:

A={6,9,11},B=ϕ

Here, B is empty set.

Therefore,

A∪B

=A∪ϕ

={6,9,11}

A intersection ϕ is ϕ I guess

If you’re willing to help, that’d be nice.

Answers

Answer:

tw ni oe haso layo esma question sodnww aokos

The sign of each y coordinate has changed

What is the next fraction in this sequence? Simplify your answer.
1/5. 7/20. 1/2. 13/20
..

Answers

Answer:[tex]a^5=\frac{4}{5}[/tex]

Step-by-step explanation:

The 5th term of the arithmetic sequence is 4/5

What is Arithmetic Progression?

An arithmetic progression is a sequence of numbers in which each term is derived from the preceding term by adding or subtracting a fixed number called the common difference "d"

The general form of an Arithmetic Progression is a, a + d, a + 2d, a + 3d and so on. Thus nth term of an AP series is Tn = a + (n - 1) d, where Tₙ = nth term and a = first term. Here d = common difference = Tₙ - Tₙ₋₁

Sum of first n terms of an AP: Sₙ = ( n/2 ) [ 2a + ( n- 1 ) d ]

Given data ,

Let the arithmetic progression be represented as A

Now , the value of A is

A = 1/5 , 7/20 , 1/2 , 13/20 ....

Now , the first term of the arithmetic sequence is a₁ = 1/5

The second term a₂ = 7/20

The common difference d = second term - first term

So , the common difference d = 7/20 - 1/5

The value of d = 3/20

Now , the nth term of the AP is given by

Tn = a + (n - 1) d, where Tₙ = nth term

Substituting the values in the equation , we get

T₅ = ( 1/5 ) + ( 5 - 1 ) ( 3/20 )

On simplifying the equation , we get

T₅ = ( 1/5 ) + ( 4 x 3 ) / 20

T₅ = 1/5 + 12/20

T₅ = 16/20

T₅ = 4/5

Therefore , the value of T₅ is 4/5

Hence , the 5th term of the arithmetic sequence is 4/5

To learn more about arithmetic progression click :

https://brainly.com/question/1522572

#SPJ2

Solve the equation 5 - (4x + 7) - 4 = 7. Explain each step of your process using a verbal
description.
I need help :/

Answers

Answer:

x = -13/4

Step-by-step explanation:

5 - (4x + 7) - 4 = 7

Distribute the minus sign

5 - 4x  -7 - 4 = 7

Combine like terms

-4x-6 = 7

Add 6 to each side

-4x-6+6 = 7+6

-4x= 13

Divide by -4

-4x/-4 = 13/-4

x = -13/4

Answer: -13/4 or -3.25 or - 3 1/4

Step-by-step explanation:

How many terms are in the expression shown?

2n+5-3p+4p

Answers

Answer:

4 terms

Step-by-step explanation:

The terms in the expression are unique in that they cannot be combined.

The 4 terms are

2n

+ 5

- 3p

+ 4p

4-3x=8-4x please help

Answers

Answer : #1= Answer:x=−4

#2=Answer:x=7

So you add 4x to both Side
After dat ya get
4+x=8 then ya gonna subtract the 4 or the both side
X=4

The circumference of a circle is 6 inches. What is the area of the circle?
r
Α= πr2
O
А Зп іn. 2 2
0 B 97 in 2
O
C. 12 in 2
O
D. 361 in 2
Review progress
Question 35
of 36
+ Back
Back
Next-

Answers

Answer:

Step-by-step explanation:

A store has a sale with 30% off every item. When you enter the store, you receive a coupon that states that you receive an additional 30% off. Is this equal to a
60% discount? Explain your answer.

Answers

Answer:

No, It is not equal to a 60% discount.

Step-by-step explanation:

Think of this. I go into a store and everything is 50% off and I have a coupon myself that is a 50% off discount for a specific item. It may seem like the item is now free, but it isn't. Imagine the item was $1 before any discount. Then the store took 50% off of the $1, leaving it at $0.50. So now with my discount of 50% off the item I will be taking this 50% off of $0.50 = my final discounted cost of $0.25.

Hope I helped you understand :)

Write the equation of the line perpendicular to 2x-5y=-12 that passes through the point (10,-1) in slope-intercept form.

Answers

Answer:

[tex]y=-\frac{5}{2}x-24[/tex]

Step-by-step explanation:

[tex]2x-5y=-12\\5y=2x+12\\y=\frac{2}{5}x+\frac{12}{5}\\[/tex]

if two lines perpendicular,

[tex]m_{1} .m_{2}=-1\\ \frac{2}{5} .m_{2}=-1\\m_{2}=-\frac{5}{2}[/tex]

the line perpendicular to this line is

[tex]y=-\frac{5}{2}x+k[/tex] ; k ∈ R

the line passes through the point (10,-1)

so,

[tex]-1=-\frac{5}{2} (10)+k\\-1=-25+k\\k=-24[/tex]

∴the equation of the line perpendicular to 2x-5y=-12 that passes through the point (10,-1) is

[tex]y=-\frac{5}{2}x-24[/tex]

Help.. Suppose Q is the midpoint of PR

Answers

Answer:

[tex]3x+41[/tex] or 38

Step-by-step explanation:

If Q is the midpoint of Line PR, then lines PQ and QR add up to equal Line PR. We then get

[tex]PQ=6x+25\\QR=16-3x\\PQ+QR=PR\\6x+25+16-3x=PR\\3x+41=PR\\[/tex]

If you want to know the exact number that PR is, we can do additional steps where PQ = QR.

[tex]PQ=6x+25\\QR=16-3x\\PQ=QR\\6x+25=16-3x\\9x+25=16\\9x=-9\\x=-1\\\\3x+41=PR\\3(-1)+41=PR\\-3+41=PR\\38=PR\\PR=38[/tex]

g(x)=2/3x-1
find g(-3)

Answers

Answer:

g(-3) = -3

Step-by-step explanation:

Plug in -3 everywhere that x is.

g(-3) = (2/3)(-3) - 1

g(-3) = (-6/3) - 1

g(-3) = -2 - 1

g(-3) = -3

Is 122/48 in its simplest form or is it’s simplest form 61/24?

Answers

The simplest form is 61/24 as your able to divide both the numerator and denominator of 122/48 by 2 to simplify it

Answer:

61/24 is its simplest form! :)

Step-by-step explanation:

Aliyana spent half of her weekly allowance on Takis. To earn more money her parents let her mow the lawn for $6. What is her weekly allowance is she ended the week with $13?

Answers

Aliyana weekly allowance is 14.

Which is larger?
1) 7/11 or 5/8
2) 5/12 or 7/9

Answers

Answer:

7/11

7/9

Step-by-step explanation:

7/11 = 35/55

5/8 = 35/56

Take the fraction eith smaller denominator

5/12 = 35/84

7/9 = 35/45

take the fraction eith the smaller denominator

write a rule in the box below that shows how to simplify a power raised to another power use A as the base and M and N as the exponents

Answers

Answer:

A is the answer of the power

Jaxon swam 100 meters in 2 minutes 30 seconds. If each lap is 25 meters long which is most likely to be her time in seconds per lap

Answers

37.5 sec/lap

Step-by-step explanation:

2 m and 30 sec to sec equals 150 sec

each lap is 25 m

100 ÷ 25 = 4 laps

150 ÷ 4 = 37.5 sec per lap

please help me solve this

Answers

Answer:

x>-1.5

Step-by-step explanation:

8k - 3 - 10 ( I have to simplify it)

Answers

8k - 3 - 10

Solution,

= 8k - 3 - 10

= 8k - 13.

Answer:

8k - 13

Step-by-step explanation:

8k - 3 - 10

-(3 - 10) = -13

= 8k - 13

Angle PRS is 98 degree. It is made of two smaller angles. One smaller angle is 3x-8 and the other one is 2x+6. What is the measure of the smaller angle?

Answers

Answer:

46

Step-by-step explanation:

The sum of the two smaller angle measures is 98.

(2x + 6) + (3x - 8) = 98

Combine like terms.

5x - 2 = 98

5x = 100

x = 20

Plug this into the expressions for the two smaller angle measures.

2x + 6 = 2(20) + 6 = 46

3x - 8 = 3(20) - 8 = 52

The smaller of the two angles measures 46.

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