1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Stels [109]
2 years ago
6

How many terms of the arithmetic sequence {1,22,43,64,85,…} will give a sum of 2332? Show all steps including the formulas used

to calculate your answer. Please don't link me any answers, I am unable to open them.
Mathematics
1 answer:
MA_775_DIABLO [31]2 years ago
4 0

There's a slight problem with your question, but we'll get to that...

Consecutive terms of the sequence are separated by a fixed difference of 21 (22 = 1 + 21, 43 = 22 + 21, 64 = 43 + 21, and so on), so the <em>n</em>-th term of the sequence, <em>a</em> (<em>n</em>), is given recursively by

• <em>a</em> (1) = 1

• <em>a</em> (<em>n</em>) = <em>a</em> (<em>n</em> - 1) + 21 … … … for <em>n</em> > 1

We can find the explicit rule for the sequence by iterative substitution:

<em>a</em> (2) = <em>a</em> (1) + 21

<em>a</em> (3) = <em>a</em> (2) + 21 = (<em>a</em> (1) + 21) + 21 = <em>a</em> (1) + 2×21

<em>a</em> (4) = <em>a</em> (3) + 21 = (<em>a</em> (1) + 2×21) + 21 = <em>a</em> (1) + 3×21

and so on, with the general pattern

<em>a</em> (<em>n</em>) = <em>a</em> (1) + 21 (<em>n</em> - 1) = 21<em>n</em> - 20

Now, we're told that the sum of some number <em>N</em> of terms in this sequence is 2332. In other words, the <em>N</em>-th partial sum of the sequence is

<em>a</em> (1) + <em>a</em> (2) + <em>a</em> (3) + … + <em>a</em> (<em>N</em> - 1) + <em>a</em> (<em>N</em>) = 2332

or more compactly,

\displaystyle\sum_{n=1}^N a(n) = 2332

It's important to note that <em>N</em> must be some positive integer.

Replace <em>a</em> (<em>n</em>) by the explicit rule:

\displaystyle\sum_{n=1}^N (21n-20) = 2332

Expand the sum on the left as

\displaystyle 21 \sum_{n=1}^N n-20\sum_{n=1}^N1 = 2332

and recall the formulas,

\displaystyle\sum_{k=1}^n1=\underbrace{1+1+\cdots+1}_{n\text{ times}}=n

\displaystyle\sum_{k=1}^nk=1+2+3+\cdots+n=\frac{n(n+1)}2

So the sum of the first <em>N</em> terms of <em>a</em> (<em>n</em>) is such that

21 × <em>N</em> (<em>N</em> + 1)/2 - 20<em>N</em> = 2332

Solve for <em>N</em> :

21 (<em>N</em> ² + <em>N</em>) - 40<em>N</em> = 4664

21 <em>N</em> ² - 19 <em>N</em> - 4664 = 0

Now for the problem I mentioned at the start: this polynomial has no rational roots, and instead

<em>N</em> = (19 ± √392,137)/42 ≈ -14.45 or 15.36

so there is no positive integer <em>N</em> for which the first <em>N</em> terms of the sum add up to 2332.

You might be interested in
You play a game on your phone. For every correct move you make, you receive 50 points. For every second that it takes you to com
swat32
50*25= 1250
2mins 15seconds= 135 seconds
135*3= 405

1250-405 = 845

Your score is 845
8 0
3 years ago
Which is the equation in slope-intercept form for the line that passes through (3, 7)
quester [9]

Answer:

y =  -  \frac{5}{3} x + 12

Step-by-step explanation:

First, rewrite the given equation in the form of y=mx+c.

m is the gradient while c is the y-intercept.

3x-5y=8

5y= 3x -8

y =  \frac{3}{5} x -  \frac{8}{5}

Thus, the gradient of the given equation is ⅗.

The product of the gradients of perpendicular lines is -1.

(gradient of line)(⅗) = -1

gradient of line= -1 ÷⅗

gradient of line= -  \frac{5}{3}

y =  -  \frac{5}{3} x + c

To find the value of c, substitute a coordinate.

When x=3, y=7,

7 =  -  \frac{5}{3} (3) + c

7= -5 +c

c= 7+5

c= 12

Hence, the equation of the line is y =  -  \frac{5}{3} x + 12.

6 0
3 years ago
Find the area of the composite figure.
Roman55 [17]

Answer:

The Area of the composite figure would be 76.26 in^2

Step-by-step explanation:

<u>According to the Figure Given:</u>

Total Horizontal Distance = 14 in

Length = 6 in

<u>To Find :</u>

The Area of the composite figure

<u>Solution:</u>

Firstly we need to find the area of Rectangular part.

So We know that,

\boxed{ \rm \: Area  \:  of \:  Rectangle = Length×Breadth}

Here, Length is 6 in but the breadth is unknown.

To Find out the breadth, we’ll use this formula:

\boxed{\rm \: Breadth = total  \: distance - Radius}

According to the Figure, we can see one side of a rectangle and radius of the circle are common, hence,

\longrightarrow\rm \: Length \:  of \:  the  \: circle = Radius

  • Since Length = 6 in ;

\longrightarrow \rm \: 6 \: in   = radius

Hence Radius is 6 in.

So Substitute the value of Total distance and Radius:

  • Total Horizontal Distance= 14
  • Radius = 6

\longrightarrow\rm \: Breadth = 14-6

\longrightarrow\rm \: Breadth = 8 \: in

Hence, the Breadth is 8 in.

Then, Substitute the values of Length and Breadth in the formula of Rectangle :

  • Length = 6
  • Breadth = 8

\longrightarrow\rm \: Area \:  of  \: Rectangle = 6 \times 8

\longrightarrow \rm \: Area \:  of  \: Rectangle = 48 \: in {}^{2}

Then, We need to find the area of Quarter circle :

We know that,

\boxed{\rm Area_{(Quarter \; Circle) }  = \cfrac{\pi{r} {}^{2} }{4}}

Now Substitute their values:

  • r = radius = 6
  • π = 3.14

\longrightarrow\rm Area_{(Quarter \; Circle) } =  \cfrac{3.14 \times 6 {}^{2} }{4}

Solve it.

\longrightarrow\rm Area_{(Quarter \; Circle) } =  \cfrac{3.14 \times 36}{4}

\longrightarrow\rm Area_{(Quarter \; Circle) } =  \cfrac{3.14 \times \cancel{{36} } \: ^{9} }{ \cancel4}

\longrightarrow\rm Area_{(Quarter \; Circle)} =3.14 \times 9

\longrightarrow\rm Area_{(Quarter \; Circle) } = 28.26 \:  {in}^{2}

Now we can Find out the total Area of composite figure:

We know that,

\boxed{ \rm \: Area_{(Composite Figure)} =Area_{(rectangle)}+ Area_{ (Quarter Circle)}}

So Substitute their values:

  • \rm Area_{(rectangle)} = 48
  • \rm Area_{(Quarter Circle)} = 28.26

\longrightarrow \rm \: Area_{(Composite Figure)} =48 + 28 .26

Solve it.

\longrightarrow \rm \: Area_{(Composite Figure)} =\boxed{\tt 76.26 \:\rm in {}^{2}}

Hence, the area of the composite figure would be 76.26 in² or 76.26 sq. in.

\rule{225pt}{2pt}

I hope this helps!

3 0
2 years ago
Logan spends 26% of his weekly allowance on 2 banana splits. Banana splits cost $3.25 each at Frozen Treats. How much money does
Shtirlitz [24]
I am not sure u should google it plz
6 0
3 years ago
What’s the answer? Will give brainliest
vodomira [7]

Answer:

Step-by-step explanation:

3

4 0
3 years ago
Other questions:
  • To get from point A to point B you must avoide walking through a pond. To avoide the pond, you must walk 34 meters south and 41
    10·2 answers
  • If you borrow $800 for 8 years at an annual interest rate of 11%, how much will you pay altogether?
    10·1 answer
  • Triangle ABC and DEF are congruent. Find x.
    10·1 answer
  • Janine’s credit card wasn’t stolen, and the thief charged a $44 meal before she reported it stolen. how much of this is Janine r
    12·1 answer
  • QUESTION 1 of 10: A Stadium sold 4,000 tickets at $75 ticket, 5,350 tickets at $62/ticket and 7,542 tickets at $49/ticket. What
    5·1 answer
  • Find the length of "a", to<br> the nearest tenth, using<br> the Pythagorean Theorem.<br> Enter
    8·1 answer
  • 7- (-11) =<br> I need the answer to this question
    10·2 answers
  • A wooden roller coaster at a theme park has a height restriction: passengers must be at least 45 inches tall.
    8·1 answer
  • Identify the solid represented by the net. A net includes 3 rectangles and 2 right triangles. The rectangles are lined up in the
    14·1 answer
  • Please everyone mark me as brainlest
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!