Find the sum
[tex]\sum_{k=1}^{\infty}\sum_{n=1}^{\infty} \frac{k}{ {2}^{n + k} } . \\ [/tex]
Correct answer will be mark as brainliest answer.​

Answers

Answer 1

[tex] \large\underline{\sf{Solution-}}[/tex]

Given series is

[tex]\rm \longmapsto\:\displaystyle\sum_{k=1}^{\infty}\rm \displaystyle\sum_{n=1}^{\infty}\rm \frac{k}{ {2}^{n + k} } [/tex]

can be further rewritten as

[tex]\rm \:  =  \: \:\displaystyle\sum_{k=1}^{\infty}\rm \displaystyle\sum_{n=1}^{\infty}\rm \frac{k}{ {2}^{k} . {2}^{n} } [/tex]

can be further rewritten as

[tex]\rm \:  =  \: \displaystyle\sum_{k=1}^{\infty}\rm \bigg[\dfrac{k}{ {2}^{k}}\displaystyle\sum_{n=1}^{\infty}\rm \dfrac{1}{ {2}^{n} } \bigg][/tex]

[tex]\rm \:  =  \: \displaystyle\sum_{k=1}^{\infty}\rm \dfrac{k}{ {2}^{k} }\bigg(\dfrac{1}{2} + \dfrac{1}{ {2}^{2} } + \dfrac{1}{ {2}^{3} } - - - \infty \bigg) [/tex]

So, its an infinite GP series with

[tex] \purple{\rm \longmapsto\:a = \dfrac{1}{2}}[/tex]

[tex] \purple{\rm \longmapsto\:r = \dfrac{1}{2}}[/tex]

We know,

Sum of infinite GP series with common ratio r ( - 1 < r < 1 ) and first term a is given by

[tex]\boxed{\tt{ \: \: S_ \infty = \frac{a}{1 - r} , \: \: provided \: that \: |r| < 1}}[/tex]

So, 1using this, we get

[tex]\rm \:  =  \: \displaystyle\sum_{k=1}^{\infty}\rm \frac{k}{ {2}^{k} }\bigg( \frac{ \frac{1}{2} }{1 - \frac{1}{2} }\bigg)[/tex]

[tex]\rm \:  =  \: \displaystyle\sum_{k=1}^{\infty}\rm \frac{k}{ {2}^{k} }\bigg( \frac{ \frac{1}{2} }{ \frac{2 - 1}{2} }\bigg)[/tex]

[tex]\rm \:  =  \: \displaystyle\sum_{k=1}^{\infty}\rm \frac{k}{ {2}^{k} }\bigg( \frac{ \frac{1}{2} }{ \frac{1}{2} }\bigg)[/tex]

[tex]\rm \:  =  \: \displaystyle\sum_{k=1}^{\infty}\rm \frac{k}{ {2}^{k} }[/tex]

[tex]\rm \:  =  \: \dfrac{1}{2} + \dfrac{2}{ {2}^{2} } + \dfrac{3}{ {2}^{3} } + \dfrac{4}{ {2}^{4} } + - - - \infty [/tex]

Let assume that

[tex]\rm \longmapsto\:S_ \infty   =  \: \dfrac{1}{2} + \dfrac{2}{ {2}^{2} } + \dfrac{3}{ {2}^{3} } + \dfrac{4}{ {2}^{4} } + - - - \infty [/tex]

Now, its an infinite Arithmetico Geometrico Series, So multiply by 1/2 we get

[tex]\rm \longmapsto\:\dfrac{1}{2} S_ \infty   =  \: \dfrac{1}{ {2}^{2} } + \dfrac{2}{ {2}^{3} } + \dfrac{3}{ {2}^{4} } + \dfrac{4}{ {2}^{5} } + - - - \infty [/tex]

On Subtracting above two equations, we get

[tex]\rm \longmapsto\:\dfrac{1}{2} S_ \infty   =  \: \dfrac{1}{2} + \dfrac{1}{ {2}^{2} } + \dfrac{1}{ {2}^{3} } + \dfrac{1}{ {2}^{4} } + - - - \infty [/tex]

[tex]\rm \longmapsto\:\dfrac{1}{2} S_ \infty   =  \: \dfrac{ \dfrac{1}{2} }{1 - \dfrac{1}{2} } [/tex]

[tex]\rm \longmapsto\:\dfrac{1}{2} S_ \infty   =  \: \dfrac{ \dfrac{1}{2} }{ \dfrac{1}{2} } [/tex]

[tex]\rm \longmapsto\:\dfrac{1}{2} S_ \infty   =  \: 1[/tex]

[tex]\bf\implies \:S_ \infty = 2[/tex]

Hence,

[tex] \\ \rm \longmapsto\:\boxed{\tt{ \: \: \: \: \displaystyle\sum_{k=1}^{\infty}\rm \displaystyle\sum_{n=1}^{\infty}\rm \frac{k}{ {2}^{n + k} } = 2 \: \: \: \: }} \\ [/tex]


Related Questions

PLEASE HELP ME WITH THIS ONE

Answers

Answer:

b answer

Step-by-step explanation:

hope helpful

if wrong sorry

Given the parent function f(x) = x2 describe the graph of g(x) = (3x-6)2 +3.

Answers

Answer:

For this case we have the following functions transformation:

Vertical expansions:

To graph y = a * f (x)

If a> 1, the graph of y = f (x) is expanded vertically by a factor a.

f1 (x) = (3x) ^ 2

Horizontal translations

Suppose that h> 0

To graph y = f (x-h), move the graph of h units to the right.

f2 (x) = (3x-6) ^ 2

Vertical translations

Suppose that k> 0

To graph y = f (x) + k, move the graph of k units up.

g (x) = (3x-6) ^ 2 + 3

Answer:

expanded horizontally by a factor of 3, horizontal shift rith 6, vertical shift up 3

Step-by-step explanation:

Answer:

For this case we have the following functions transformation:

Vertical expansions:

To graph y = a * f (x)

If a> 1, the graph of y = f (x) is expanded vertically by a factor a.

f1 (x) = (3x) ^ 2

Horizontal translations

Suppose that h> 0

To graph y = f (x-h), move the graph of h units to the right.

f2 (x) = (3x-6) ^ 2

Vertical translations

Suppose that k> 0

To graph y = f (x) + k, move the graph of k units up.

g (x) = (3x-6) ^ 2 + 3

Answer:

expanded horizontally by a factor of 3, horizontal shift rith 6, vertical shift up 3

PLEASE help me answer this question!!

Answers

$2,875
IIIIIIIIIIIIIII

What is 93.195 written in expanded form?

Answers

Standard Form:

93.195

Expanded forms can be written like a sentence or stacked for readability as they are here.

Expanded Notation Form:

 93.195 =

 90  

+ 3  

+   0.1

+   0.09

+   0.005

Expanded Factors Form:

   93.195 =

 9 × 10  

+ 3 × 1  

+ 1 ×   0.1

+ 9 ×   0.01

+ 5 ×   0.001

Expanded Exponential Form:

 93.195 =

9 × 101

+ 3 × 100

+ 1 × 10-1

+ 9 × 10-2

+ 5 × 10-3

Word Form:

93.195 =

ninety-three and one hundred ninety-five thousandths

20 points and brainliest!
Express each sentence below as an equation or inequality.
1. Bob has two less than half of the document of points Leroy has.
2. To be in the platinum tier for a ranked video, you must have at least 1000 ranked points.

Answers

Answer

Step-by-step explanation:

B=Bob, b=2-(1/2xL)

L= leroy

P<1000

60 POINTS PLS HELP WILL MARK BRAINLIEST EXPLAIN TOO PLS

Answers

Step-by-step explanation:

we need to find the slope of each line.

the slope is the ratio y/x indicating how many units y changes, when x changes a certain amount of units.

parallel lines have the same slope.

for a perpendicular line x and y in the slope ratio are put upside down, and the sign is flipped (+ to - and vice versa).

a.

2x - 8y = -24

2x + 24 = 8y

y = 2/8 x + 24/8 = 1/4 x + 3

the slope is 1/4 (always the factor of x).

4x + y = -2

y = -4x - 2

the slope is -4 = -4/1.

this line is therefore perpendicular to the first line.

x - 4y = 4

x - 4 = 4y

y = 1/4 x - 4/4 = 1/4 x - 1

the slope is 1/4.

this line is therefore parallel to the first line.

b.

3x - 9y = 9

9y = 3x - 9

y = 3/9 x - 9/9 = 1/3 x - 1

the slope is 1/3

3y = x + 12

y = 1/3 x + 4

the slope is 1/3.

this line is therefore parallel to the first line.

2x - 6y = 12

6y = 2x - 12

y = 2/6 x - 12/6 = 1/3 x - 2

the slope is 1/3.

this line is therefore parallel to the first line.

Is 3 to the second power + 3 to the 3rd power equal to 3 to the 5th power explain

Answers

Answer:

They are not equal.

Step-by-step explanation:

Hi there!

[tex]3^2+3^3[/tex] is not equal to [tex]3^5[/tex]. When two powers with the same base are added together, we cannot add the exponents to get the answer.

We can only add exponents to get the answer when two power with the same base are multiplied.

[tex]3^2+3^3\\= 9+27\\=36[/tex]

[tex]3^5\\=243[/tex]

They are not equal.

I hope this helps!

What is the length of segment HK?

Answers

[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪  {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]

Let's take length of HK = n

By using trigonometry,

[tex] \sin(30) = \dfrac{22}{n} [/tex]

[tex] \dfrac{1}{2} = \dfrac{22}{n} [/tex]

[tex]n = 44[/tex]

Hence, value of HK = 44 cm

[tex]\\ \rm\Rrightarrow sin\theta=\dfrac{Perpendicular}{Hypotenuse}[/tex]

[tex]\\ \rm\Rrightarrow sin30=\dfrac{JK}{HK}[/tex]

[tex]\\ \rm\Rrightarrow sin30=\dfrac{22}{HK}[/tex]

[tex]\\ \rm\Rrightarrow HK=\dfrac{22}{sin30}[/tex]

[tex]\\ \rm\Rrightarrow HK=44[/tex]

When the same probability is assigned to each outcome of a sample space, the experiment is said to have _______ ________ outcomes.

Answers

Answer:

Equally likely

Step-by-step explanation:

Hope this is right!

the answer is Equally likely :)))

Sketch the graph of this linear equation
4y = -7x + 1​

Answers

Answer:

use desmos to graph it

.....

Please help! Geometry practice was lines cut by a transversal. What is the value of X?

Answers

Answer:

x = 70

Step-by-step explanation:

1. First, we need to know that the angle with 45 degrees and the angle with (2x-5) degrees are same-side interior angles, meaning they add up to 180 degrees. The equation of this can be written as so: [tex]2x-5+45= 180[/tex]

2. (Solving)

Step 1: Combine like terms.

[tex](2x) +(-5+45) = 180[/tex] [tex]2x + 40 = 180[/tex]

Step 2: Subtract 40 from both sides.

[tex]2x + 40 - 40 = 180 - 40[/tex] [tex]2x = 140[/tex]

Step 3: Divide both sides by 2.

[tex]\frac{2x}{2} = \frac{140}{2}[/tex] [tex]x = 70[/tex]

Step 4: Check if solution is correct.

[tex]2(70) - 5 + 45 = 180[/tex] [tex]140 - 5 + 45 = 180[/tex] [tex]135 + 45 = 180[/tex] [tex]180 = 180[/tex]

Therefore, x = 70.

You buy 50 feet of fence to place around a rectangular yard. If the length of the yard is 13 feet, what is the constraint for the width of the yard? Let w represent width *

Answers

Step-by-step explanation:

a fence represents the circumference, the perimeter of the lot or yard.

remember, a rectangle has 2 parallel sides called the length, and 2 parallel sides called the width (altogether 4 sides).

therefore

perimeter = 2×length + 2×width

or with short variables

p = 2×l + 2×w

so, now we have 50 ft of fence available for the perimeter. and the length l = 13 ft.

since we have 2 lengths in the perimeter, these 13 ft are twice (2×13 = 26 ft) in the perimeter.

now, how much fence do we have left for the width ?

well, 50 - 26 = 24 ft

and again, this is the size of 2 sides (2×width) :

p = 2×l + 2×w

50 = 2×13 + 2×w = 26 + 2×w

2×w = 24

w = 12 ft

so, the width of the yard must not be bigger than 12 ft.

what do many prefixes and suffixes have in common?

Answers

Prefixes and suffixes are both types of affixes.

We need to find the combined total of 1,203,000,000 and 2,345,000,000. Write your answer in scientific notation.
PLZ answer quick, 30 points

Answers

Answer:

answer in scientific notation.

PLZ answer quick, 30 points

What is the area of the trapezoid?

Answers

the area is 160 cm^2

Middle school math pls help

Answers

Answer:

2 3/4

Step-by-step explanation:

You need to find the greatest common factor of 4 and 2 then you multiply the 2 by 2 to get a 4 and multiply the 1, then you add those together to get 2 3/4.

Take away -7x from {2y-2x}

Answers

Answer:

loading, please wait...

Step-by-step explanation:

Answer:

2y + 5x

Step-by-step explanation:

{ 2y - 2x } - ( - 7x )

= 2y - 2x + 7x

= 2y + 5x

WILL GIVE BRAINLIEST 5x-5=4x+10​

Answers

X=15

5x-5=4x+10
Add 5 both sides
5x=4x+15
Subtract 4 on both sides
1x=15
Divide 1
X=15
X=15 should be correct

Enter the number in scientific notation.
0.00000174 =
X10
Hint: Move the decimal right 6 places.

Answers

Answer:

1.74 X 10^-6

Step-by-step explanation:

Hope It helps

Which expression is equivalent to 11+22q+22-5q I’ll give the crown just pls answer

Answers

Answer:

[tex]11 + 22q + 22 - 5q \\ = 33 + 17q[/tex]

9+10=21 yay

bababooey

Two similar cups are 3cm and 5cm deep,if the longer cup has 625cm of water.what is the volume of the smaller one​

Answers

Answer:

81

Step-by-step explanation:

the 5 cm deep cup is 625 which is 5^4

that means that the 3cm deep cup should be 81 which is 3^4

help me with this pelases

Answers

Answer:

32 square units

Step-by-step explanation:

You can split this shape into four different shapes:

2 unit by 2 unit triangle

2 unit by 2 unit square

2 unit by 6 unit triangle

To find the length of the big triangle, add the lengths of the small triangle,the square,and the bigger leg of the other triangle:

2 + 2 + 6 = 10

10 unit by 4 unit triangle

Then solve all these areas:

( 2 x 2 ) / 2 = 4 / 2 = 2

2 x 2 = 4

( 2 x 6 ) / 2 = 12 / 2 = 6

( 10 x 4 ) / 2 = 40 / 2 = 20

Then add all these areas together to get the total area of the composite shape:

2 + 4 + 6 + 20 = 32

The GCD of three numbers is 7 and their LCM is 140.If one of the numbers is 20,find the other number​

Answers

Formula= LCM×GCD of the numbers÷The Given number

Which of the following is a characteristic of a line?

Answers

[tex]\huge\rm\purple{\underline{Line:-}}[/tex]

➜ A line is a figure in geometry which has only length with no breadth in a two dimensional plane , and extended infinitely in opposite directions .

➜ A line may be of any length and breadth . An infinite number of combination of long, short , thick or thin lines can Accord to their application unify , divide , balance , or unbalance a pictorial area . This emotion dynamic is set up by lines measures .

⠀⠀━━━━━━━━━━━━━━━━━━━━━━━━━━━━⠀⠀

[tex]\large\sf\orange{\underline{Characteristics\:of\:line:}}[/tex]

Line type : dotted , short dashed , long dashed and continuous line.Line width : extra dark , thick , medium annd thinLine quality : the quality of line depends largely upon the drawing medium

⠀⠀━━━━━━━━━━━━━━━━━━━━━━━━━━━━⠀⠀

Please help with this math problem! Will give brainliest! :)

Answers

Answer:

9

Step-by-step explanation:

All triangles (3 sided polygons) have angles added up to 180, so we can do the following:

(7x-1) + (7x+8) + (5x+2) = 180° - equation

7x-1 + 7x+8 + 5x+2 = 180° - "distribute"

19x - 1 + 8 + 2 = 180° - combine the x terms

19x + 9 = 180° - combine the integer terms

19x = 171 - subtract 9 form both sides

x = 9 - divide both sides by 19

A company’s stock was selling at $25 a share. A month later, $30 a share. What is the precent increase

Answers

Answer:

20 %

Step-by-step explanation:

5 divided by 20 equals x 100

Write the amount in standard scientific notation.
3.65E-2 millimeters

Answers

The answer to the question is 0.0365

Photo above need help

Answers

Slope = rise/run = 3/5
The slope is 3/5 which is rise/run

please help, numbers 14 & 16 only. thank you so much, I’ll mark brainliest.

Answers

14. 37/50

16. 13/40

I just converted each fraction into a decimal.

18/25 = 0.72

3/4 = 0.25

11/35 is approximately 0.314

5/14 is approximately 0.357

Then choose a decimal in between and converted it back

What is the rate of change over the interval [-1,2] for f(x)= 4x +1

Answers

Answer:

4

Step-by-step explanation:

To find the average rate of change, we have to plug in the difference between the intervals with this equation: f(b) - (fa) / x₂ - x₁

Let f(a) = f(-1) = 4(-1) + 1

     f(b) = f(2) = 4(2) + 1

     x₂ = 2

     x₁ = -1

[4(2) + 1 - (4(-1) + 1)] / [2 - (-1)]

[8 + 1 + 4 - 1] / [3]

12 / 3 = 4

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