if the sum of the first n terms of the series 4+7+10+..... is 209, find n​

Answers

Answer 1

Answer:

Step-by-step explanation:

wow, this is kinda complicated math for HS..  :?   we have to know what type of series this is, and that means knowing all the different kinds.. unless maybe in the instructions it tells you you are working with arithmetic series? It is one of those so we can use those formulas... other series can have much more complex formulas..  series comes up in Calc II in college.. but .. unless you're going to be an engineer you probably don't need it..  soooooo anyway..

we can use  Sn = n/2(2a1 + d(n-1) )

where d is the difference of a2 -a1 ( this will be the same for all terms)

since we're given Sn = 209 set the problem to 209 and solve for n  :/

sounds hard huh.. :?  let's see

209 = n/2( 2(4) + 3(n-1))

209 = n/2(8 + 3n-3)

209 = n/2(5+3n)

2*209 = n(5+3n)

418 = 3[tex]n^{2}[/tex] + 5n

0 = 3[tex]n^{2}[/tex] + 5n-418    ( use quadratic formula to find n )

( -5 ± [tex]\sqrt{5^{2}-4*3*(-418) }[/tex]  ) / 2(3)

( -5 ±[tex]\sqrt{25+5016}[/tex] ) / 6

( -5 ±[tex]\sqrt{5041}[/tex] ) / 6

( -5 ± 71 ) / 6  ( they were nice to us and make it work out perfectly :)  )

positive route =  71-5 /6 = 66/6 =11

negative route = 71-(-5) /6  = 71+5/6 = 76/6 = 12[tex]\frac{2}{3}[/tex]

since 12[tex]\frac{2}{3}[/tex]  isn't going to really work for us... let's try 11

an= a1 + d(n-1)

an = 4 + 3(11-1)

an = 4 + 30

an = 34

now let's see if we can get 209 for our 11 terms of the series

Sn = 11/2(2(4) + 3(11-1))

Sn = 11/2(8 + 30)

Sn = 418 /2

Sn = 209  yay.. we got it.. it's the 11th term.. and thank you  quadratic formula.  You get a Christmas present this year  :P

n = 11

Answer 2

The number of the terms of the sequence will be equal to 11.

What is an arithmetic progression?

The sequence in which every next number is the addition of the constant quantity in the series is termed the arithmetic progression.

Given series is  4+7+10+.....  and the sum of the terms of the series is 209.

The summation of the n terms of the series is written by the formula below,

Sn = n / 2 [( 2a+(n-1)d]

Substitute the values in the equation above,

209 = n / 2 [(2 x 4 + ( n -1)3]

418 = n(5+3n)

3n² + 5n - 418 = 0

The above quadratic equation will give two values of n. The values of n are,

n = 11

n = -12.55

The terms can not be equal to a negative number.

Therefore, the number of the terms of the sequence will be equal to 11.

To know more about arithmetic progression follow

https://brainly.com/question/24205483

#SPJ2


Related Questions

Find the 6th term 9 18 36

Answers

Answer:

I think the answer is 288.

Step-by-step explanation:

The rule seems to be multiplying the past number by 2. So, 9*2=18 and 18*2=36. If we continued that rule we would then get 72, 144, and the sixth term is then 288.

hope this helps :D

Answer:

Step-by-step explanation:

This is a geometric sequence because any term divided by the previous term is a constant called the common ratio. r=36/18=18/9=2 A geometric sequence is expressed as

[tex]a_n=ar^{n-1},\text{ where a=initial term, r=common ratio, n=term number}\\ \\ a_n=9(2^{n-1})\\ \\ a_6=9(2^5)\\ \\ a_6=288[/tex]

HELP ASAP! What is the slope of the line???

Answers

Answer: the slope is 1

Step-by-step explanation:

Slope is basically rise over run. Looking at the graph you see it rises one unit and then goes over to the left by one unit. 1÷1 equals 1 so That is your slope.

this is a quiz on special right triangles. please help me i cannot fail this. i will mark brainliest

Answers

Answer:

x=4

Step-by-step explanation:

Consider ΔKLJ:

sinθ=opposite/hypotenuse

sin30=LJ/8√2

LJ=0.5*8√2=4√2

Consider ΔMLJ:

sinθ=opp/hyp

sin45=x/4√2

1/√2=x/4√2

4√2/√2=x

x=4

please help me answer​

Answers

If you multiply you get 24cm
it is 24 centimeters.

Find the value of X, Z, and Y in the graph below?

Answers

9514 1404 393

Answer:

  (x, y, z) = (49, 58, 122)

Step-by-step explanation:

The same-side exterior angles have a sum of 180°.

  (x +9) +(3x -25) = 180

  4x -16 = 180

  x -4 = 45

  x = 49

Vertical angles are congruent:

  y = 49 +9 = 58

  z = 180 -y = 122 = 3(49) -25

The values of x, y, and z are ...

X = 49Z = 122Y = 58

the graph of y = 4x^2 - 4x - 1 is shown use the graph to find estimates for the solutions of a and b

Answers

Answer:

a) -0.25 and 1.25

b) -0.5 and 1.5

Step-by-step explanation:

a) For 4x^2-4x -1 = 0

What we have to do here is to simply find he points on the x-axis in which the graph crosses it

we have this as;

approximately-0.5 and 1.5

what we are saying is that the plot crosses the x-axis at x = -0.25 and x = 1.25

ii) what we have to do here is to find the point at which y = 2

After finding this point, we trace it to the plot sideways, before we trace to the x-axis

By tracing, we have the crossing on the x-axis at these points at -0.5 and 1.5

Joe pays $4.20 per carton for fresh eggs from the farmers’ market.
If x represents the number of egg cartons and y is the total cost, which of the following representations contains an error?

Answers

4.20 -$+$+"$8(#83+78$88873888#9

How do I graph this?

Answers

F. Toy r rus is closed for good

A used book store also started selling used CDs and videos. In the first week, the store sold a combin
ation of 40 CDs and videos. They charged $4 per CD and $6 per video
and the total sales were $180. Determine the total number of CDs and videos sold
Set up two equations, one for number of CD's and videos sold and one for amount of money
made. Then solve for each variable by graphing in Desmos. Clearly state your answers in a
sentence.

Answers

Answer:

300 cds

Step-by-step explanation:

because 60x3=180 and 40 divied by 4 is 10.

SOMEONE HELP ME IS DUE TODAY PLZ

Answers

Answer:

good luck

Step-by-step explanation:

good luck

How do you solve this (for x) and what is the answer for x?

Answers

Answer:

Area for a rectangle-

l x b

(x + 5)+ (2x) =110

3x=110-5

x=105/3

x=35

Thus the answers are-

2 x 35

=70

35 + 5

=40

Please help, I’ll give brainliest

Answers

Answer:

2 more hours

Step-by-step explanation:

1 1/2 + 2 1/6 = 1 3/6 + 2 1/6 = 3 4/6 = 3 2/4

3 2/3 - 1 2/3 = 2


What is the measure of the arc in the
picture above?
I will make BRAINLIEST !

Answers

Answer:

9.42 km

Step-by-step explanation:

Measure of the arc

[tex] = \frac{ \theta}{360 \degree} \times 2\pi r \\ \\ = \frac{45 \degree}{360 \degree} \times 2 \times 3.14 \times 12 \\ \\ = \frac{1}{8} \times 75.36 \\ \\ = 9.42 \: km[/tex]

AL

2

In a high school stadium there are 750 seats. There are twice as many seats in the home

section as there are in the visitor section. Which system of equations could be used to

determine the number of seats in the home section, h, and the number of seats in the

visitor section, v, in the stadium?



PLEASE HELP HURRY PLEASEEE

Answers

Answer:

There are 250 home section and 2(250) = 500 visitor section.

Step-by-step explanation:

Let there are h number of seats in the home section and v is the number of seats in the visitor section.

h+v = 750 ...(1)

There are twice as many seats in the home  section as there are in the visitor section.

v = 2h ...(2)

From equations (1) and (2).

h+2h = 750

3h = 750

h = 250

Hence, there are 250 home section and 2(250) = 500 visitor section.

The distance between point Q and point P is 6 1/2 units .Which number could represent point Q?please help me

Answers

Answer:

[tex]Q =2\frac{1}{2}[/tex] or [tex]Q =- 10\frac{1}{2}[/tex]

Step-by-step explanation:

Given

[tex]P = -4[/tex] --- missing from the question

[tex]Distance = 6\frac{1}{2}[/tex]

Required

Determine the possible value of Q

The distance can be calculated using absolute function as:

[tex]Distance = |Q - P|[/tex]

Substitute values for distance and P

[tex]6\frac{1}{2} = |Q - (-4)|[/tex]

[tex]6\frac{1}{2} = |Q +4|[/tex]

The absolute function can then be split as:

[tex]6\frac{1}{2} = Q + 4[/tex] or [tex]-6\frac{1}{2} = Q + 4[/tex]

Make Q the subject in both cases:

[tex]Q = 6\frac{1}{2} - 4[/tex] or [tex]Q = -4 - 6\frac{1}{2}[/tex]

[tex]Q =2\frac{1}{2}[/tex] or [tex]Q =- 10\frac{1}{2}[/tex]

WILL GIVE BRAINLIST AND LOST OF PIONTS!!!!!!!!!!!PLEASE HELP!!!
The community library charges a late fee of $0.25 per day for every book that is overdue. The charge for a video is shown in the table. Soren checks out one book and one video and returns them 5 days late. What is the total he will pay in late fees?

5 day video late fee: $

5 day book late fee: $

Total 5 day late fee: $

Answers

Answer:

5 day book fee would be $1.25 and 5 day video is $2.25 + 1.25= $3.50

Step-by-step explanation:

Answer:

$10.00

Step-by-step explanation:

Fee for book: $0.25 * 5  = $1.25

Fee for day: $1.75 * 5 = $8.75

Total fee: $1.25 + $8.75 = $10.00

pls answer guys if you do you get something good

Answers

Answer:

10 pounds of barley

Step-by-step explanation:

Answer:

10

Step-by-step explanation:

7*5=35

therefore, 2*5=10

Write a system of equations to describe the situation below, solve using any method, and fill in the blanks.

An event organizer is reserving rooms for two company-wide events. For the quarterly meeting this month, she reserved 3 conference rooms and 5 ballrooms, which can seat a total of 399 attendees. For safety training next month, she reserved 1 conference room and 5 ballrooms, which can seat 363 attendees. How many attendees can each room accommodate?

Answers

Answer:

x=18 y=69

Step-by-step explanation:

3x+5y=399

x+5y=363

2x=36

x=18

18+5y=363

5y=345

y=69

Find the area of a triangle with a base of 3 cm and height of 8 cm

Answers

Answer: The area of a triangle is 12cm²

Answer:

8 x 3 = 24cm

Step-by-step explanation:

8 + 8 + 8 = 24cm

or

3 + 3 + 3 + 3 + 3 + 3 + 3 + 3 = 24cm

Solve for x: -30 - 5x = 120

A. X = -18

B. X = -30

C. X = 30

D. X = 18​

Answers

Answer:

B. X = -30

Step-by-step explanation:

Answer:

b. -30

Step-by-step explanation:

 -30 - 5x = 120

+30           +30

-5x = 150

150 / - 5 = -30

i answered first can i have brainliest?

what is the slope of the line that passes through the points (3,-2) and (9,-2)? 0 3 -3 undefined

Answers

Answer:

[tex]\boxed{\textsf{ The slope of the line is $\bf{\dfrac{3}{2}}$.}}[/tex]

Step-by-step explanation:

Two points are given to us and we need to find the slope of the line that passes through these two points . The two points are (3,-2) and (9,-2) .As we know that the slope of the line is given by [tex]\tan\theta[/tex]

Slope of a line is :-

[tex]\qquad\boxed{\boxed{ \sf Slope =\dfrac{ y_2-y_1}{x_2-x_1}=\tan\theta }}[/tex]

On using this formula we can find the slope of the line .

Putting the respective values :-

[tex]\sf\implies Slope = \dfrac{y_2-y_1}{x_2-x_1}\\\\\sf\implies Slope = \dfrac{ 9-3}{2+2} \\\\\sf\implies Slope =\dfrac{6}{4}\\\\\sf\implies\boxed{\pink{\sf Slope = \dfrac{3}{2} }}[/tex]

Answer:

Its zero -w-

Step-by-step explanation:

The measures of the legs of a right triangle both measure 7 yards. What is the length of the hypotenuse? Round your answer to the nearest tenth.

Answers

[tex] {a}^{2} + {b}^{2} = {c}^{2} [/tex]

[tex] {7}^{2} + {7}^{2} = {98}^{2} [/tex]

[tex] \sqrt{98} = 9.9 \: yards[/tex]

A French restaurant used 555,580 ounces of cream last year. This year, due to a menu update, it used 45% less. How much cream did the restaurant use this year?

Answers

Answer:

305,569 ounces of cream.

Step-by-step explanation:

Take 45% and turn it into a decimal, which is 0.45.Multiply 555,580 by 0.45. This is 250,011Since the keyword is less, we want to subtract 555,580 by 250,011. This is 305,569. This is your answer.

1/2 divided by 4 what does that =

Answers

Answer:

1/8

Step-by-step explanation:

Answer:

The answer is 0.125

Step-by-step explanation:

Hope this helps

Find the area plzzzzzzxxxzzxxxzzzzzzz

Answers

Step-by-step explanation:

step 1. break up the shape into 2 triangles and one rectangle

step 2. A = area of triangle 1 (t1) + area of triangle 2 (t2) + area of the rectangle (r)

step 3. t1 = (1/2)bh where b is the base and h is the height. definition of the area of a triangle.

step 4. t1 = (1/2)(3)(2) = 3ft^2.

step 5. t2 = (1/2)(3)(3) = 4.5ft^2.

step 6. r = bh where b is the base and h is the height. definition of the area of a rectangle.

step 7. r = bh = (8)(4) = 32ft^2.

step 8. A = t1 + t2 + r = 3 + 4.5 + 32 = 39.5ft^2.

Lin's sister has a checking account. If the account balance ever falls below zero, the bank charges her a fee of $5.95 per day. Today, the balance in Lin's sister's account is -$2.67. In 14 days, Lin's sister will be paid $430 and will deposit it into her checking account. If there are no other transactions besides this deposit and the daily fee, will Lin continue to be charged $5.95 each day after this deposit is made? Explain or show your reasoning.

Answers

Answer: No, the bank will not keep charging her the $5.95 after the deposit is made.

Step-by-step explanation:

Today, Lin's sister's balance is -$2.67

She gets charged $5.95 per day.

There are 14 days until she can charge some money in the bank account, so the bank will charge $5.92 14 times

So her balance after 14 days will be:

Balance = -$2.67 - $5.95*14 = -$85.97

When she charges the $430 in the account, her balance will be:

Balance = -$85.97 + $430 = $344.03

So now she has a positive balance, which means that the bank does not charge her anymore.

Sally cycle 14 miles north and 13 miles east. To return to her starting points she took the shortest distance shown in the diagram by the dotted line

Answers

Answer:

Step-by-step explanation:

There's no diagram and no question, but I assume it shows a right triangle.

distance = √(14²+13²) = √365 ≅ 19.1 miles

The length of an object, f(x), in yards, is a linear function of the length of the object, x, in feet. What units should be used to describe the rate of change in f(x) with respect to x?

A.
Inches per foot

B.
Feet per yard

C.
Yards per foot

D.
Yards per inch

Answers

Answer:

DADDY CHILL

Step-by-step explanation:

...........The answer is B

Llam is setting up folding chairs for a meeting. If he arranges the chairs In 7 rows of the same length, he has 5 chairs left over. If he arranges the chairs in 5 rows of that same length, he has 23 left over. How many chalrs does Llam have?​

Answers

Liam has total 40 chairs with him

POPULATION In 2000, the world population was calculated to be 6,071,675,206. The world population increases at a rate of about 1.2% annually.

Write a function that represents the world population y after x years.

A) y = 6,071,675,205(1.012)^x

B) y = 6,071,675,206(1.012)^x

C) y = 6,071,605,205(1.012)^x

D) y = 6,071,675,215(1.012)^x

PLEASE HELP!!

Answers

Answer:

B) y = 6,071,675,206(1.012)^x

Step-by-step explanation:

It appears that this question asks for an exponential model that represents the population growth. I believe you could view the equation in the form y = (initial population)(rate)^x

Since the initial population is 6,071,675,206, you could substitute that in to get y = 6,071,675,206(rate)^x

Since your rate is increasing by 1.2% (0.012 in decimal form), just convert that to decimal form (knowing that 100% = 1.0, add 0.012 to get 1.012). Substitute that in to get y = 6,071,675,206(1.012)^x

Hope that helps. Feel free to let me know if it made sense.

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