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Anita505

  • one year ago

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

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  1. inkyvoyd
    • one year ago
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    The question is, will you give your calculator a medal if you did the same thing? ;)

  2. inkyvoyd
    • one year ago
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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.

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

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

  5. Anita505
    • one year ago
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    @SithsAndGiggles

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

  7. Anita505
    • one year ago
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    how?

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

  9. inkyvoyd
    • one year ago
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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

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

  11. inkyvoyd
    • one year ago
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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.

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

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

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

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

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

  17. inkyvoyd
    • one year ago
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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?

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

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

  20. Anita505
    • one year ago
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    oops right**

  21. inkyvoyd
    • one year ago
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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

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

  23. inkyvoyd
    • one year ago
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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?

  24. Anita505
    • one year ago
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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

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

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

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

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

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

  30. inkyvoyd
    • one year ago
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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 :)

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

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

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

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

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

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