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Anita505

  • 2 years ago

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

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

  2. inkyvoyd
    • 2 years 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
    • 2 years ago
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    |dw:1363038798101:dw|

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

  5. Anita505
    • 2 years ago
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    @SithsAndGiggles

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

  7. Anita505
    • 2 years ago
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    how?

  8. Anita505
    • 2 years 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
    • 2 years 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
    • 2 years ago
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    |dw:1363039261135:dw|

  11. inkyvoyd
    • 2 years 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
    • 2 years ago
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    section 4.5 The Gauss Jordan method for calculating Inverses.

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

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

  15. Anita505
    • 2 years ago
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    oh yes haha sorry about that. :p

  16. Anita505
    • 2 years ago
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    |dw:1363039743929:dw|

  17. inkyvoyd
    • 2 years 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
    • 2 years ago
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    we want to get a 1

  19. Anita505
    • 2 years ago
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    on the bottom left corner

  20. Anita505
    • 2 years ago
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    oops right**

  21. inkyvoyd
    • 2 years 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
    • 2 years ago
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    @inkyvoyd can you please draw out the matrix solution? this is very confusing.. to understand ahah

  23. inkyvoyd
    • 2 years 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
    • 2 years 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
    • 2 years ago
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    |dw:1363062987282:dw|

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

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

  28. inkyvoyd
    • 2 years ago
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    Tell me what your answer is :)

  29. Anita505
    • 2 years ago
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    1 I -3 0 I 1

  30. inkyvoyd
    • 2 years 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
    • 2 years ago
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    so -15 I 16 3 I 16 is what u got?

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

  33. Anita505
    • 2 years ago
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    ohh okay they are in fractions oh okay thank you!

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

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

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