A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

Need help on a couple Limit Problems, precalculus. Find limit as x approaches two from the left of f of x. and limit as x approaches two from the right of f of x..

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

    @Zale101

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

    I'm just confused whether it is 4;-2 or -2;4 @Zale101

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

    What's the actual limit though ? I mean, find the limit as x approaches 2 bla bla bla - of what ?

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

    Find limit as x approaches two from the left of f of x. and limit as x approaches two from the right of f of x..

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

    |dw:1439684924826:dw|

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

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

    That's what I am given @AngusV

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

    @Zale101

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

    Oh, well that's different.

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

    So I figured out two limits are 4; -2 just not sure in what order.

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

    Well, you know that line you see above and below the Ox axis is your function - the f of x - right ?

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

    Yes

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

    Put yourself "in the position" of that line as you are approaching x=2 from below: The simplest way to imagine this would be to consider "yourself" as 1.99999999.... Since you're less than 2 now, you would have to find yourself on the above line, where f(x)=4. Thus, the limit of f(x) when you are approaching 2 from "below" is 4.

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

    If you were to approach x=2 from "above" - imagine yourself as being 2.00001 and you see that for x=2.000001, f of x or y=-2.

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

    Ok...I understand how to find limits. Just not sure what order they go in after?

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

    Judging by the phrasing, it says : find the limit bla bla bla as x approaches from the left, find the limit bla bla bla as x approaches from the right. So since the answer for the left approach is 4 and for the right approach is -2 It would be 4;-2

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

    Oh ok!

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

    Could you help me with a couple others? @AngusV

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

    I'll do my best.

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

    Ok thanks!

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

    @AngusV ^

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

    It is...whatever you can make out to be on the left side. Looks like 1.something.

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

    1.3?

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

    Use graphs and tables to find the limit and identify any vertical asymptotes of limit of 1 divided by the quantity x minus 9 as x approaches 9 from the left. Would it be positive infinity; x=9?

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

    @AngusV

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

    And for: Use graphs and tables to find the limit and identify any vertical asymptotes of limit of 1 divided by the quantity x minus 7 squared as x approaches 7. Would this be ok? Using a graph, I see that as you approach 7 from the left, then you get positive infinity.

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

    @AngusV

  28. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    For \(\displaystyle \lim_{x\to9^-}\dfrac1{x-9}\), no it's not positive infinity. You are correct about 7 part, but problem just said "x approaches" 7, which means x approaches 7 from BOTH sides.

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

    Oh! So negative infinity; x=7?

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

    Oh sorry, I meant negative infinity; x=9

  31. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yep. You can imagine this way: \(\dfrac1{x-9}\) is same as \(\dfrac1x\), but shifted 9 units right.

  32. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    So is everything clear?

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

    Yes, just that other problem. Use graphs and tables to find the limit and identify any vertical asymptotes of limit of 1 divided by the quantity x minus 7 squared as x approaches 7. Would this be ok? Using a graph, I see that as you approach 7 from the left, then you get positive infinity. Just wanted to make sure I worded it correctly

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

    @geerky42

  35. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Not really. Problem is \(\large\displaystyle\lim_{x\to7}\dfrac1{(x-7)^2}\) And you are basically saying that \(\large\displaystyle\lim_{x\to7}\dfrac1{(x-7)^2}=\infty \) because \(\large\displaystyle\lim_{x\to7^-}\dfrac1{(x-7)^2}=\infty\) What about right side?

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

    Could I say: Using a graph, I see that as you approach 7 from the left, then you get positive infinity. When you approach 7 from the right side, then you get negative infinity?

  37. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Why negative infinity for right side?

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

    I'm not sure. I'm confused by this entire question. @geerky42

  39. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Did you graph \(\dfrac1{(x-7)^2}\)?

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

    Yes @geerky42

  41. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    It looks something like this, right?|dw:1439687480641:dw| From left sides, what does it approaches to? Right sides?

  42. geerky42
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Just imagine dot approaching to x=7 (on left side for now), what value of y would this dot approaches to?|dw:1439687675392:dw|

  43. 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.