A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

cherrilyn

  • 5 years ago

∫dx/(x^2+6x+6)^2 Evaluate the integral by completing the square and using trig substitution. After completing the square I got (x+3)^2-3 but I don't know what to do next

  • This Question is Closed
  1. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    your good with the completing the square part: [(x+3)^2 +6+9)]^2

  2. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you are adding +9 inside; so you add +9 outside as well....

  3. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    wiat...-9 lol

  4. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    your right there...good job :)

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

    lols amistre, "good job" :P

  6. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you need to substitute the trig..... x^2 -1 thing....

  7. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    tan = x^2 + 1 sin = 1 - x^2 whats the other one? sec?

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

    don't trig sub needed amistre what is with you and trig subbing!?!?! those are the worst!!! just to regular subbing

  9. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    its in the prob itself...use trig sub lol :) not my fault this time lol

  10. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    sec^2 - 1 = tan...i think thats the one...

  11. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    x = sqrt(3) sec(t)

  12. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    err.... (x+3) = sqrt(3)sec(t) 3sec^2(t) -3 = 3(sec^2(t)-1) [3tan^2(t)]^2 = 9 tan^4(t)

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

    the integral of (x+3)^2-3 is \[\frac{1}{3}(x + 3)^3 - 3x\]

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

    oy i should learn to read the question... amistre, i take everything back...

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

    ...but what i did was right...why do you need trig id?

  16. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    d(sqrt(3) sec(t))/dt = ....everything? even the ceramic unicorn you gave me for my birthday?

  17. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    d(sqrt(3) sec(t))/dt = d(x+3)/dx sqrt(3) sec(t)tan(t) dt = dx [sqrt(3) sec(t)tan(t) dt]/[9 tan^4(t)] is this looking right ;)

  18. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    \[\int\limits_{} \frac{\sqrt{3} \sec(t) \tan(t)}{9 \tan^4 (t)}dt\]

  19. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    we can ignore for the moment the sqrt(3)/9 reduce to: sec(t)/tan^3(t) = sin(t)/cos^4(t)

  20. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you sure you posted the question right?

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

    yeah I just don't know how to add the division bar . lol . "Evaluate the integral by completing the square and using trigonometric substitution"

  22. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    frac{top}{bottom} in the editor :)

  23. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    any ideas how to integrate: sin(t) ----- ?? cos^4

  24. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    sin(t) = sqrt(1-cos^2) sqrt(1-cos^2) ------------ doesnt seem to make it easier cos^4

  25. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    cos^2 = 1-sin^2 (1-sin^2)(1-sin^2) = sin^4 -2sin^2 +1...... hmmm

  26. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    D(tan^4) = 4 tan^3 sec^2....dont see that helping lol

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

    No conclusion ? :(

  28. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i couldnt get to a result.....at leaast not without pencil and paper to do it with.... and a lot more braincells :)

  29. 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.