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anonymous

  • 5 years ago

a) Find the product of the 2 matrices below showing all your working. [2 7] [3 8] [-1 4] [5 0] b) Find the product of the 2 matrices below showing all your working and explain the significance of this result. [3 8] [2 7] [5 0] [-1 4] If A= [7 8] [5 2] Find A^-1

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  1. anonymous
    • 5 years ago
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    hm.. how to do this one..?

  2. amistre64
    • 5 years ago
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    i believe its... 2.3+7.5 2.8+7.0 -1.3+4.5 -1.8+4.0

  3. anonymous
    • 5 years ago
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    hm.. I don't know whether it's right or wrong..

  4. amistre64
    • 5 years ago
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    its right for a

  5. amistre64
    • 5 years ago
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    2.3 means 2(3)... just in a lazy format

  6. anonymous
    • 5 years ago
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    its like this: (2x3)+(7x5) (8x2)+(7x0) (-1x3)+(4x5) (-1x8)+(4x0)

  7. amistre64
    • 5 years ago
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    6+35 = 41 16+0 = 16 -3+20=17 -8+0=-8

  8. anonymous
    • 5 years ago
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    Yup, I got the answer for a.. but, I'm stuck in b and c...

  9. anonymous
    • 5 years ago
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    do the same process in b

  10. anonymous
    • 5 years ago
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    yep

  11. anonymous
    • 5 years ago
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    how to explain the significance of this result??

  12. amistre64
    • 5 years ago
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    b is the same process: [3 8] [2 7] [5 0] [-1 4] 3.2+8.-1 = -2 3.7+8.4= 53 5.2+0.-1= 10 5.7+0.4=35

  13. amistre64
    • 5 years ago
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    c; find the inverse... [7 8] 7.a+8.c=1 7.b+8.d=0 [5 2] 5.a+2.c=0 5.b+2.d=1

  14. anonymous
    • 5 years ago
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    in part c its doing the nverse, do you know the proces of doing it?

  15. amistre64
    • 5 years ago
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    [a b] [c d] will be the inverse

  16. amistre64
    • 5 years ago
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    the short cut is to flip and negate the 7 and 2 :)

  17. amistre64
    • 5 years ago
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    it is the 7 and 2 right?

  18. amistre64
    • 5 years ago
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    flip a d and negate b c

  19. amistre64
    • 5 years ago
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    [2 -8] [-5 7]

  20. anonymous
    • 5 years ago
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    ok I've flipped a d and negate b c..

  21. amistre64
    • 5 years ago
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    that is the inverse of A :)

  22. anonymous
    • 5 years ago
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    ok thank you..! So after inverse, there's nothing else right?

  23. anonymous
    • 5 years ago
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    yup amistre got it,, theres nothing else

  24. anonymous
    • 5 years ago
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    Thanks so much guys!

  25. anonymous
    • 5 years ago
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    wc

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