A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

Help with arithmetic/geometric sequences and series problem please

  • This Question is Closed
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    The problem is in the attached file

  2. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what does is mean by describe the four quantities? Don't the quantitates mean the same thing in all four formulas?

  3. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    the quantities are the the variables like a_1,n,d,a_n in the problem a and a_1,n,r,a_n in problem c

  4. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    do you know what a_1 means?

  5. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    the subscript there basically tells you

  6. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    for example a_6 is the 6th term in the sequence

  7. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    which choice a or c represents an arithmetic sequence ? and of those choices one if a geometric sequence. an example of an arithmetic sequence is 3,7,11,15,... notice each term minus it's previous is the same number this number is the common difference an example of a geometric sequence is 2,4,8,16,... notice each term divided by its previous is the same number this number is the common ratio what do you think the d represents ? what do you think the r represents?

  8. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    d represents the difference and r represents the common ratio @freckles

  9. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    great d represents the common difference of an arithmetic sequence and r represents the common ratio of a geometric sequence

  10. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I'm confused though because in the problem it says to describe the four quantities for each formula, but would the quantities be the same in each formula

  11. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    for example wouldn't a_1 mean the first term in the sequence no matter what formula it is?

  12. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @freckles

  13. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes a_1 can mean the first term in the sequence

  14. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok, so how do I answer the second part of the question? @freckles

  15. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I don't know which 3 to use for example in a do they want us to use a_1, n, and d to find a_n or do they want us to use a_1,a_n,n to find d or do they want us to use a_n,n,d to find a_1 or do they want us to use a_1,a_n,d to find n or do they want us to do each possibility of what they could mean

  16. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I'm not sure about that either, I'm assuming they want us todo each possibility. Could you just show me how to do it for 1 of the formulas and I can figure it out for the other ones? @freckles

  17. freckles
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    \[a_n=a_1+d(n-1) \\ \text{ if we have } a_1,d, \text{ and } n \text{ just follow the order of operations \to find } a_n \\ \\ a_n=a_1+d(n-1) \\ \\ \text{ if we have } a_n,a_1,n \text{ then we can find } d \text{ by doing } \\ a_n-a_1=d(n-1) \text{ subtract } a_1 \text{ on both sides } \\ \frac{a_n-a_1}{n-1}=d \text{ divided both sides by} (n-1) \\ \] then you can do something similar for the other two possibilties just solve the equation for n also solve the equation for a_1

  18. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok so it's pretty simple

  19. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    thanks!

  20. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.