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
kirill115 [55]
2 years ago
15

Find the circumferences of both circles | would be greatly appreciated if someone answered :) ^^

Mathematics
2 answers:
Darina [25.2K]2 years ago
7 0
It’s gonna be 69.08 I believe
Strike441 [17]2 years ago
6 0
The answer is 69.08!
You might be interested in
2,17,82,257,626,1297 next one please ?​
In-s [12.5K]

The easy thing to do is notice that 1^4 = 1, 2^4 = 16, 3^4 = 81, and so on, so the sequence follows the rule n^4+1. The next number would then be fourth power of 7 plus 1, or 2402.

And the harder way: Denote the <em>n</em>-th term in this sequence by a_n, and denote the given sequence by \{a_n\}_{n\ge1}.

Let b_n denote the <em>n</em>-th term in the sequence of forward differences of \{a_n\}, defined by

b_n=a_{n+1}-a_n

for <em>n</em> ≥ 1. That is, \{b_n\} is the sequence with

b_1=a_2-a_1=17-2=15

b_2=a_3-a_2=82-17=65

b_3=a_4-a_3=175

b_4=a_5-a_4=369

b_5=a_6-a_5=671

and so on.

Next, let c_n denote the <em>n</em>-th term of the differences of \{b_n\}, i.e. for <em>n</em> ≥ 1,

c_n=b_{n+1}-b_n

so that

c_1=b_2-b_1=65-15=50

c_2=110

c_3=194

c_4=302

etc.

Again: let d_n denote the <em>n</em>-th difference of \{c_n\}:

d_n=c_{n+1}-c_n

d_1=c_2-c_1=60

d_2=84

d_3=108

etc.

One more time: let e_n denote the <em>n</em>-th difference of \{d_n\}:

e_n=d_{n+1}-d_n

e_1=d_2-d_1=24

e_2=24

etc.

The fact that these last differences are constant is a good sign that e_n=24 for all <em>n</em> ≥ 1. Assuming this, we would see that \{d_n\} is an arithmetic sequence given recursively by

\begin{cases}d_1=60\\d_{n+1}=d_n+24&\text{for }n>1\end{cases}

and we can easily find the explicit rule:

d_2=d_1+24

d_3=d_2+24=d_1+24\cdot2

d_4=d_3+24=d_1+24\cdot3

and so on, up to

d_n=d_1+24(n-1)

d_n=24n+36

Use the same strategy to find a closed form for \{c_n\}, then for \{b_n\}, and finally \{a_n\}.

\begin{cases}c_1=50\\c_{n+1}=c_n+24n+36&\text{for }n>1\end{cases}

c_2=c_1+24\cdot1+36

c_3=c_2+24\cdot2+36=c_1+24(1+2)+36\cdot2

c_4=c_3+24\cdot3+36=c_1+24(1+2+3)+36\cdot3

and so on, up to

c_n=c_1+24(1+2+3+\cdots+(n-1))+36(n-1)

Recall the formula for the sum of consecutive integers:

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

\implies c_n=c_1+\dfrac{24(n-1)n}2+36(n-1)

\implies c_n=12n^2+24n+14

\begin{cases}b_1=15\\b_{n+1}=b_n+12n^2+24n+14&\text{for }n>1\end{cases}

b_2=b_1+12\cdot1^2+24\cdot1+14

b_3=b_2+12\cdot2^2+24\cdot2+14=b_1+12(1^2+2^2)+24(1+2)+14\cdot2

b_4=b_3+12\cdot3^2+24\cdot3+14=b_1+12(1^2+2^2+3^2)+24(1+2+3)+14\cdot3

and so on, up to

b_n=b_1+12(1^2+2^2+3^2+\cdots+(n-1)^2)+24(1+2+3+\cdots+(n-1))+14(n-1)

Recall the formula for the sum of squares of consecutive integers:

1^2+2^2+3^2+\cdots+n^2=\displaystyle\sum_{k=1}^nk^2=\frac{n(n+1)(2n+1)}6

\implies b_n=15+\dfrac{12(n-1)n(2(n-1)+1)}6+\dfrac{24(n-1)n}2+14(n-1)

\implies b_n=4n^3+6n^2+4n+1

\begin{cases}a_1=2\\a_{n+1}=a_n+4n^3+6n^2+4n+1&\text{for }n>1\end{cases}

a_2=a_1+4\cdot1^3+6\cdot1^2+4\cdot1+1

a_3=a_2+4(1^3+2^3)+6(1^2+2^2)+4(1+2)+1\cdot2

a_4=a_3+4(1^3+2^3+3^3)+6(1^2+2^2+3^2)+4(1+2+3)+1\cdot3

\implies a_n=a_1+4\displaystyle\sum_{k=1}^3k^3+6\sum_{k=1}^3k^2+4\sum_{k=1}^3k+\sum_{k=1}^{n-1}1

\displaystyle\sum_{k=1}^nk^3=\frac{n^2(n+1)^2}4

\implies a_n=2+\dfrac{4(n-1)^2n^2}4+\dfrac{6(n-1)n(2n)}6+\dfrac{4(n-1)n}2+(n-1)

\implies a_n=n^4+1

4 0
3 years ago
___% of $10 = $2<br> Please help me I can not figure it out <br> I need it please
kherson [118]

Answer:

20 :)

Step-by-step explanation:

5 0
2 years ago
Read 2 more answers
Help me please I don’t understand
ankoles [38]
A² + b² = c²
8² + x² = 16²
x² = 16² - 8²
x² = 192
x =√192
x =8√3
5 0
3 years ago
Read 2 more answers
On my sister's 15th birthday, she was 159 cm in height, having grown 6% since the year before. How tall was she the previous yea
Zarrin [17]
It means that her height in this year is 106\%x in regards to the last year, where x is her height in last year, so:

159=106\%x

159=\frac{106}{100}x

159=\frac{53}{50}x

159*50=53x

159*50=53x

7950=53x

150=x
8 0
3 years ago
A newborn calf weighs about 90 pounds. Each week, it's weight increases by 5%. a) If we were to graph this growth, would it be a
AlladinOne [14]

Answer: exponential because it's a ratio :)

Step-by-step explanation:

5 0
3 years ago
Read 2 more answers
Other questions:
  • Evaluate 5/3
    6·2 answers
  • If PQRS is a parallelogram with two adjacent congruent sides, then ___________________.
    6·2 answers
  • Write a conditional statement for a following Venn diagram
    13·1 answer
  • What is the slope of the line passing through the points (1, -5) and (4,1)
    7·2 answers
  • Alaska has a land area of about 1,700,000 square kilometers. Florida has a land area 10 the size of Alaska. What is the land are
    12·1 answer
  • Takes a word processor 20 minutes to spell check 6 pages, how long to check 27 pages
    6·1 answer
  • Adonis bought a pair of shoes that were on sale for 25% off. If Zakee paid $120 for the shoes, how much money did he save, compa
    9·1 answer
  • HELP AND EXPLAIN PLSS
    7·1 answer
  • How to solve this.im stuck in this question for 20 mins. Plzz answer
    6·1 answer
  • B(1)= 160, b(n) = b(n-1) * 0.5 for n (g/e) 2 determine the first 4 items in a sequence given this recursive formula.
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!