prove that Sn=n(n+1) for the sequence an=2n,where n is any positive integers​

Answers

Answer 1

Answer:

Proved

Step-by-step explanation:

Given

[tex]a_n = 2n[/tex]

Required

Prove that [tex]S_n = n(n+1)[/tex]

The given sequence is an arithmetic sequence.

The Sn of this sequence is:

[tex]S_n = \frac{n}{2}(a_1 + a_n)[/tex]

Calculate a1

[tex]a_n =2n[/tex]

[tex]a_1 =2*1[/tex]

[tex]a_1 =2[/tex]

So, we have:

[tex]S_n = \frac{n}{2}(a_1 + a_n)[/tex]

[tex]S_n = \frac{n}{2}(2 + 2n)[/tex]

Factor out 2

[tex]S_n = \frac{n*2}{2}(1 + n)[/tex]

[tex]S_n = n(1 + n)[/tex]

[tex]S_n = n(n + 1)[/tex] --- Proved


Related Questions

impact of humour in specific language structure​

Answers

Answer:

Summary

Interest in the linguistics of humor is widespread and dates since classical times. Several theoretical models have been proposed to describe and explain the function of humor in language. The most widely adopted one, the semantic-script theory of humor, was presented by Victor Raskin, in 1985. Its expansion, to incorporate a broader gamut of information, is known as the General Theory of Verbal Humor. Other approaches are emerging, especially in cognitive and corpus linguistics. Within applied linguistics, the predominant approach is an analysis of conversation and discourse, with a focus on the disparate functions of humor in conversation. Speakers may use humor pro-socially, to build in-group solidarity, or anti-socially, to exclude and denigrate the targets of the humor. Most of the research has focused on how humor is co-constructed and used among friends, and how speakers support it. Increasingly, corpus-supported research is beginning to reshape the field, introducing quantitative concerns, as well as multimodal data and analyses. Overall, the linguistics of humor is a dynamic and rapidly changing field.Step-by-step explanation:

help me pls and be serious or I’ll hurt u

Answers

Answer:

-9

Step-by-step explanation:

Khan Academy huh? Well, the answer's -9.

-7 = -9 + 2

Hope that helps!

what is 0.46 as a fraction in simplest form, a fraction of 100, and a percent​

Answers

Answer:

46/100

23/50

46%

Answer:

bleh

Step-by-step explanation:

so that da other guy can get brainliest

Volume of of 7cm 4cm 5cm

Answers

140cm yes this is totally the answer

Answer:

140

Step-by-step explanation:

You multiply 7 by 4 you get 28. Then multiply 28 by 5 you get 140.

Hans purchased 29.4 centimeters of wire for 14.70$. Find the unit price in dollars per centimeter

Answers

Answer:

$0.50/cm

Step-by-step explanation:

Find the area of a triangle with a base of 7 cm and a height of 3 cm.
21 cm squared
10.5 cm squared
20 cm squared
10 cm squared

Answers

Answer:

10.5 cm

Step-by-step explanation:

took the test

June's flower bed has a length of 8 feet and a width of seven eighths feet. Is the area of the flower bed larger, smaller, or equal to 8 square feet?

Answers

Answer:

it would be larger. the square footage is 56 square feet.

Step-by-step explanation:

What’s 59+(h-11) ??????

an orange paint mixture uses 3 cups of red paint for every 5 cups of yellow paint. how many cups of yellow paint will one cup of red paint be for.​

Answers

respuesta : 8 espero tesirba

(a) An angle measures 61°. What is the measure of its supplement?
(b) An angle measures 39'. What is the measure of its complement?

Answers

Answer:

61+x=180

x=180-61

x=119

y+39=90

y=90-39

y=51

Answer:

(a)119°

(b)51°

Step-by-step explanation:

(a)Subtract the given angle from 180.

=180°-61°

=119° (The supplement of 61° is 119°)

(b)Subtract the given angle from 90.

=90°-39°

=51° (The complement of 39° is 51°)

find the value of y and (4x+8)°​

Answers

Answer:

A

Algebra For what values of the variables must ABCD be a parallelogram?

B

23. A 2y + 2 B 24. B

(3x + 10)

(8x + 5)º

3x + 6

54°

D

С

D

A

Зу - 9 с

ly+4

Help me, please............

Answers

Answer:

67%

350/ 210 -1 = .67 x 100%

Answer:

67%

Step-by-step explanation:

21/35

Please help me Answer this :)
( Will give brainlst!!)

<3

Answers

Answer:

( it's below)

Step-by-step explanation:

a. electron

b. proton

c. neutron

d. electron shell

Answer:

a:Electron

b:proton

C:neutron

d:electron shell

Choose the symbol that goes in the blank to make the statement true.
96,000 _ 128,000 = < >

Answers

Answer:

<

Step-by-step explanation:

hhahaha

Find the equation of a line perpendicular to -3x + 5y = -1 that contains the point (0, -5)

Answers

Answer:

y = -5/3x - 5

Step-by-step explanation:

convert -3x + 5y = -1 to slope-intercept form:

5y = 3x - 1

y = 3/5x - 1/5

slope of a line perpendicular to the above equation would be -5/3

y = mx + b

-5 = -5/3(0) + b

b = -5

y = -5/3x - 5

Use the given points to answer parts 1, 2, and 3. Include all of your work in your final answer. Type your answer in the box provided or use the upload option to submit your
solution.
(6, 1) and (5, 4)
Part 1: Find the slope of theline that passes through the given points, (6, 1) and (6,4).
Part 2: Write the point-slope form of the line that passes through the points (6, 1) and (5, 4).
Part 3: Write the slope-intercept form of the line that passes through the points (6, 1) and (5, 4).

Answers

Answer:

Write the point-slope form of the line that passes through the points (6, 1) and (5, 4).

Step-by-step explanation:

A garden table and a bench cost $793 combined. The garden table costs $43 more than the bench. What is the cost of the bench?​

Answers

Answer:

The bench costs $375

Step-by-step explanation:

t + b = 793

t = b+43

(b+43) + b = 793

2b + 43 = 793

2b = 750

b = 375

The bench costs $375

375$ :) im
sorry if its in correct i tried my best

what is the perimeter, in centimeters, of a right triangle that has leg lengths of 8centimeters and 11 centimeters? round to the nearest tenth

Answers

Answer:

90

Step-by-step explanation:

8 x 11 = 88

So now you have to add 2 to get to the nearest 10. ;)

Place the following Numbers in order -5.2, - 28/5 , 1 8/11 , 3/2

Answers

Hello!

So, I didn’t know if you wanted me to put them from (Least to Greatest) or (Greatest to Least).. So, I did both.

(LEAST TO GREATEST):

3/2, 1 8/11, -28/5, -5.2

________________________________

(GREATEST TO LEAST):

-5.2, -28/5, 1 8/11, 3/2

________________________________

There you go, I hope this helps! Have a great day/night and stay safe! :)

Just pick the one that you were suppose to find the answer for. :)

What are the slope and y intercept of the linear function that is represented by the table

Answers

Answer:

Slope of the line is 3

Y-intercept is (3/2) three-halves

Explanation:

I saw this also on Brainly! Hope this helps! :)

In rectangle ABCE, AC is the diagonal. BD⟂AC at O. AB = 13, OA=5. Find the length of OD and OB
plz answer with explanation

Answers

Answer:

ABCD is a parallelogram. The diagonals AC and BD intersect at O. If AB = 6 cm, = AC = 11 cm and BO =3.5 cm what is the length of AD?

The diagonals AC and BD bisect each other, therefore AO = OC = 5.5 cm.

The area of triangle AOB = COD = [s(s-a)(s-b)(s-c)]^0.5

Here a = 6, b = 5.5, c = 3.5, so 2s = 15 or s = 7.5. So

[s(s-a)(s-b)(s-c)]^0.5 = [7.5(7.5–6)(7.5–5.5)(7.5–3.5)]^0.5

= [7.5*1.5*2*4]^0.5

= 90^0.5 sq cm

Area of triangle ADC = 2 x area of triangle AOB = 2*90^0.5 sq cm, or

2*90^0.5 = [(s1(s1-p)(s1-q)(s1-r)]^2, squaring both sides we get

4*90 = [s1(s1-p)(s1-q)(s1-r)]

360 = s1(s1–11)(s1–6)(s1-AD) … (1)

2s1 = AD + 11 + 6 = AD + 17, or

s1 = 8.5 + 0.5AD … (2). Put the value of s1 from (2) in (1) to get

360 = (8.5 + 0.5AD)(8.5 + 0.5AD-11)(8.5 + 0.5AD-6)(8.5 + 0.5AD-AD)

360 = (8.5 + 0.5AD)(0.5AD-2.5)(0.5AD+2.5)(8.5 - 0.5AD)

360 = (8.5^2 - 0.5AD^2)(0.25AD^2–6.25)

= - (8.5^2 - 0.5AD^2)(6.25 - 0.25AD^2)

= - (72.25 -0.5AD^2)(6.25 - 0.25AD^2)

360 = - [451.5625 -18.0625AD^2 - 3.125AD^2 + 0.125AD^3], or

-360 = 451.5625 -18.0625AD^2 - 3.125AD^2 + 0.125AD^3, or

0.125AD^3 - 21.1875 AD^2 + 451.5625 + 360 = 0, or

0.125AD^3 - 21.1875 AD^2 + 811.5625 = 0, or

AD^3 - 168.5 AD^2 + 6492.5 = 0, or

By trial and error, AD = 6.3272

Check: AD^3 - 168.5 AD^2 + 6492.5

6.3272^3 - 168.5*6.3272^2 + 6492.5

253.3- 6745.6 + 6492.5 = 0.2 as against 0

Hence AD = 6.3272 cm.

Answer:

Assuming you really mean the rectangle is ABCD, not ABDE:

Since DB is perpendicular to AC, it must be square.

If OA = 5, then OB = OC = OD = 5

This isn't possible because the triangle made by ABO would be a right triangle and AO^2 + BO^2 would equal AB^2. It does not.

5^2 + 5^2 =AB^2 = 7.07, not 13

Which statement about the graph of y
3x + 5 is correct?

A. The line passes through the ordered pair (3,0) and has a slope of 5.

B. The line passes through the ordered pair (0,5) and has a slope of 3.

С. The line passes through the ordered pair (5,20) and has a slope of 5/3

D. The line passes through the ordered pair (3, 14) and has a slope of 3/5

Answers

It is B as 5 is the y intercept in the equation. Checked with a graphing calculator. B is the answer

The correct statement for the equation of the line is the line passes through the ordered pair (0,5) and has a slope of 3.

What is an equation of the line?

An equation of the line is defined as a linear equation having a degree of one. The equation of the line contains two variables x and y. And the third parameter is the slope of the line which represents the elevation of the line.

The general form of the equation of the line:-

y = mx + c

m = slope

c = y-intercept

Slope = ( y₂ - y₁ ) / ( x₂ - x₁ )

Compare the given equation of the line y = 3x + 5 with the general equation.

y = mx + c

y = 3x + 5

The slope, m = 3

y-intercept = 5

To know more about an equation of the line follow

https://brainly.com/question/18831322

#SPJ2

A prehistoric site was discovered. The site is a nearly perfect circle

Answers

Answer:

whats the question

Step-by-step explanation:

a pack of pens cost $3. Prisha spent $12 on pens. Each pack has 5 pens How many packs did Prisha buy?

Answers

Answer: 4

Step-by-step explanation: I think

$12 divided by $3/pack = 4 packs of pens.


4 packs x 5 pens = 20 pens (if there’s a follow-up question)

What is the probability that a value picked at random from the standard normal distribution will be between -1.96 and 1.96?

Answers

Answer:

P( -1.96 ≤ Z≤ 1.96) = 0.95

Step-by-step explanation:

Explanation:-

Given that the z -scores -1.96 and 1.96

we have to find   P( -1.96 ≤ Z≤ 1.96)

P( -1.96 ≤ Z≤ 1.96) = |A(1.96)+A(-1.96)|

                              = |A(1.96)+A(-1.96|   (∵A(-Z) = A(Z))

                            =  0.4750+0.4750

                            = 2×0.4750

                           = 0.95

The probability lies between  -1.96 to 1.96

P( -1.96 ≤ Z≤ 1.96) = 0.95

             

What is log5x=4 in exponential form

Answers

Answer:

Step-by-step explanation:

If you mean log₅(x) = 4, take the antilog₅ of both sides.

x = 5⁴

Which is larger:
A. the absolute value of 12
B. the absolute value of -15

Answers

Answer:

A

Step-by-step explanation:

I am pretty sure this is right and I hope this helps

Answer:

B. the absolute value of -15

Step-by-step explanation:

Ok so,

lets rewrite them for it to make sense

| 12 |  = 12

| - 15 | = 15

so now the question is "which is larger 12 or 15?" and the answer is 15 obvs lol

" | " = means absolute value

hope this helps have a good day!

If a cable repairman is supposed to show up to for a repair between 1:00pm and 6:00pm and the home owner can’t be homeuntil 3:00pm, what is the probability that the home owner will be home when the cable repair man shows up (assuming the repairman is equally likely to come at any time during the specified range)?

A) 60%
B) 65%
C) 70%
D) 75%

Answers

Answer:

60%

Step-by-step explanation:

3/5 likely, because there are five hours when the repairman could show up.

Three of them will have the homeowner, and 2 would not. 3/5=0.6=60%

Answer:

for da other guy to get brainliest

Step-by-step explanation:

A farmer owns a strip of land next to an interstate. It is 1 mile long and 1/6 mile wide. What is the area of this strip of land in square miles?

Answers

Answer:

1/6 square miles

Step-by-step explanation:

lw=a

1*1/6=1/6

Answer:

1/6 square mlies

Step-by-step explanation:

PLS HELP IF YOU ANSWER I WILL GIVE BRAINLIEST ANSWER!

Answers

Townnet I believe im sorry if I’m wrong

evaluate 3 + jk + k3 when j = 2 and k = 6.​

Answers

Answer:

231

Step-by-step explanation:

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