Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Life

  • 3 years ago

Write each arithmetic series as the sum of terms, find each sum.

  • This Question is Closed
  1. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1354173691072:dw|

  2. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    this one's different

  3. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    how do i find a_1

  4. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    is it -5?

  5. sagarrobo
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1354173877445:dw| put k=10 and get answer

  6. sagarrobo
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    answer=1000-275=725

  7. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    does a_1 =-5 ?

  8. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \(a_1\) is the result of the equation when you plug your first term into it. Your equation is \(100-5k\). The series starts when k = 1, so plug 1 in for k and solve. That's \(a_1\).

  9. sagarrobo
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    100-5k is general term for k series so first term=95

  10. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what about a_n, |dw:1354174176642:dw|

  11. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    its wrong i know...

  12. sagarrobo
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    its wrong refer to my solution above in figure

  13. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @Life: You need to distinguish between the formula for the sum of the series and the equation you're given (in this case, 100-5k). You need to find the value for \(a_{10}\), and then plug that into your series summation formula.

  14. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \(a_1 = 95\) (you solved that already). \(a_{n} = a_{10} = 100-5(10)\) Plug \(a_{1}\), \(a_{10}\) (which is the *value* you get—*not* 10), and \(n\) into your \(S_{n}\) formula and solve.

  15. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i dont understand how "I" got 95, i never did, but i undetstand everything after that, i thought a1=-5

  16. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Your equation is \(100-5k\), so \(a_{1}\) will be the result you get when you plug 1 in for \(k\).

  17. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \(a_{2}\) will be the result you get when you plug in 2 for \(k\). \(a_{3}\) will be the result you get when you plug in 3 for \(k\). ... \(a_{10}\) will be the result you get when you plug in 10 for \(k\).

  18. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @Life: Have you ever done computer programming? If so, do you know what a for loop is?

  19. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    That's all a series is. For each value from what's below sigma to what's above it (in this case, between k=1 and k=10), perform the equation. Once you know each one, add them all together.

  20. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    my final answer, s10=725, AM I RIGHT? :)

  21. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yes.

  22. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    sorry for being dumb lol, i understand it now though, so it was all worth it

  23. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    You're not being dumb. You are showing effort (not just "what's the answer?"), which is appreciated. :)

  24. geoffb
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Good luck with the rest of them. I have faith that you'll get them all. Good night. :)

  25. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Good night :D

  26. Life
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I really do appreciate you sticking with me until i understood it. It was probably a good half an hour before I finally understood it, so thanks a bunch

  27. 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