Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

LOOSEr

what is a 3x3 invertible matrix?

  • one year ago
  • one year ago

  • This Question is Closed
  1. tkhunny
    Best Response
    You've already chosen the best response.
    Medals 0

    Are you OK with what a 3x3 matrix is?

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

    do you want a formal definition or a solved example showing all steps of inverting a 3x3 matrix?

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

    a solved example would be great

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

    ok

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

    @mathsmind ???

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

    which means its determinant cant be 0?

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

    yest i will show you the full steps

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

    consider the following matrix

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

    PLZ continue

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

    \[A=\left[\begin{matrix}1 & -2 & 0\\ 3& 1 & 5\\ -1 & 2 & 3\end{matrix}\right]\]

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

    Step one: \[A^T\]

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

    which means transpose of rows and columns of A

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

    \[A^T=\left[\begin{matrix}1 & 3 & -1\\ -2& 1 & 2\\ 0 & 5 & 3\end{matrix}\right]\]

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

    Step Two: find the adjoint or adjugate of A, which implies that we replace each element by their cofactor...

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

    If P = \begin{bmatrix} a &b &c \\ d &e &f \\ g &h &i \end{bmatrix}

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

    now please concentrate on this step it is simple but requires a bit of accuracy

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

    And P^4=2P how can we find P

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

    let's finish this first part then i will come to the 2nd question, you asked me first for a numerical example

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

    so we need to find adjA

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

    I know how to find a inverse matrix. So, can u plz do the 2nd question

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

    ok sure

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

    any idea?

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

    yes sorry am on the phone, but just a quick hint for P^n we use the principle of induction

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

    i will show you shortly

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

    @mathsmind ???

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

    @mathsmind why is taking so long?

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

    sorry back, am at work

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

    now P^4 means you are multiplying your matrix by itself 4 times.

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

    yep

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

    you know how to multiply the, it would be PP=P^2, then P^2P=P^3. then P^3P=P^4

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

    But it would be really long

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

    well this is the world of Matrices...

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

    are you thinking of algebraic operation on matrices such as taking the inverse of 2P

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

    or subtracting p^4-2P=0 in order to find the new P?

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

    Isn't there any short way

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

    have you done hermitian matrices...

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

    nope

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

    listen can we kindly finish this tonight because it is 5 am and i need to go ...

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

    okay

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

    i will provide you with full solution even if you are not online ok

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

    see ya tonight

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

    @ParthKohli

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

    lol, you still here? I thought you got help

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

    No

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

    can u do it?

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

    Short way

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

    I haven't done matrices yet: I am stuck with number theory at the moment.

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

    Nope.

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

    http://www.wikihow.com/Inverse-a-3X3-Matrix

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

    @looser there are many matrices such that P^4=2P but only one is invertible which is |dw:1361026643638:dw|

    • one year ago
    • Attachments:

See more questions >>>

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.