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Anita505 Group Title

Find the inverse of the following matrix A, if possible. Check that... WILL GIVE A MEDAL :)

  • one year ago
  • one year ago

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  1. inkyvoyd Group Title
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    The question is, will you give your calculator a medal if you did the same thing? ;)

    • one year ago
  2. inkyvoyd Group Title
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    If you own a graphing calculator, chances are you will be able to use it to do this math problem. I'm assuming that this is NOT homework OR testwork. If it is, I'll try to work you through the problem.

    • one year ago
  3. Anita505 Group Title
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    |dw:1363038798101:dw|

    • one year ago
  4. Anita505 Group Title
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    sorry we are not suppose to use a graphing calculator actually.

    • one year ago
  5. Anita505 Group Title
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    @SithsAndGiggles

    • one year ago
  6. inkyvoyd Group Title
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    In this case, you might have to give us the matrix A in order to start...

    • one year ago
  7. Anita505 Group Title
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    how?

    • one year ago
  8. Anita505 Group Title
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    can u show me the steps on finding this solution? please i dont understand what i did wrong

    • one year ago
  9. inkyvoyd Group Title
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    Well, you might want to type the A matrix because I can't find the inverse of the matrix without the matrix itself xD

    • one year ago
  10. RadEn Group Title
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    |dw:1363039261135:dw|

    • one year ago
  11. inkyvoyd Group Title
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    Also, please tell me the name of the unit/course you are taking at the moment. There are a number of ways to find the inverse of a matrix. I'm assuming you are using determinants or Gauss-Jordan elimination, but if you are using something else please let me know.

    • one year ago
  12. Anita505 Group Title
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    section 4.5 The Gauss Jordan method for calculating Inverses.

    • one year ago
  13. inkyvoyd Group Title
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    Okay. Please tell me what matrix A is. I mean, the four numbers...

    • one year ago
  14. RadEn Group Title
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    lol, @Anita505 can u draw ur matrix according in ur book :)

    • one year ago
  15. Anita505 Group Title
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    oh yes haha sorry about that. :p

    • one year ago
  16. Anita505 Group Title
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    |dw:1363039743929:dw|

    • one year ago
  17. inkyvoyd Group Title
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    Begin with your matrix and the identity matrix. Now, you want to make the left hand side the identity matrix, and the right hand side will be the inverse. Use elementary row operations. 6 5|1 0 2 7|0 1 Let's multiply the second row by 3, so that first number is also 6 6 5 |1 0 6 21|0 3 Now subtract the first row from the second row REMEMBER: We want the left hand side to be the identity matrix! 6 5 |1 0 0 16|-1 3 The zero in the bottom left is a start - we want to keep going. What do you think we should do next?

    • one year ago
  18. Anita505 Group Title
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    we want to get a 1

    • one year ago
  19. Anita505 Group Title
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    on the bottom left corner

    • one year ago
  20. Anita505 Group Title
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    oops right**

    • one year ago
  21. inkyvoyd Group Title
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    Yes. so we simply divide the that bottom row by 16. 6 5 |1 0 0 1|-1/16 3/16 Next we'll find the top row by subtracting 5 times the second row 6 0|21/16 -15/16 0 1|-1/16 3/16 finally divide row one by 6. I'ma check my work to see if I got it correct xD - tell me what you got xD

    • one year ago
  22. Anita505 Group Title
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    @inkyvoyd can you please draw out the matrix solution? this is very confusing.. to understand ahah

    • one year ago
  23. inkyvoyd Group Title
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    I'm afraid I can't do that - what I will do is tell you if what you get agrees with what I get. Is that fair?

    • one year ago
  24. Anita505 Group Title
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    okay so what did u get for the first row and first column, first row and second column, and what did u get for the second row first column and second row second column

    • one year ago
  25. Anita505 Group Title
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    |dw:1363062987282:dw|

    • one year ago
  26. inkyvoyd Group Title
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    Can you tell me what you got, so I can check your answer? :)

    • one year ago
  27. Anita505 Group Title
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    my answer is incorrect tho thats why i asked u to show me what u did :p

    • one year ago
  28. inkyvoyd Group Title
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    Tell me what your answer is :)

    • one year ago
  29. Anita505 Group Title
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    1 I -3 0 I 1

    • one year ago
  30. inkyvoyd Group Title
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    6 0|21/16 -15/16 0 1|-1/16 3/16 this is where I left off. This is only one step left - use a single easy elementary operation to make the left hand the identity matrix. and the right hand will be your answer :)

    • one year ago
  31. Anita505 Group Title
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    so -15 I 16 3 I 16 is what u got?

    • one year ago
  32. inkyvoyd Group Title
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    No... the correct matrix is 7/32 -5/32 -1/16 3/16

    • one year ago
  33. Anita505 Group Title
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    ohh okay they are in fractions oh okay thank you!

    • one year ago
  34. inkyvoyd Group Title
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    yes, my bad http://www.bluebit.gr/matrix-calculator/calculate.aspx

    • one year ago
  35. Anita505 Group Title
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    thank you can u help me with a few more questions?

    • one year ago
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