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December 6th, 2010, 03:52 PM   #1
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Help with Matrix problem

I do not now how to do these types of problems. Could somebody point me in the right direction?

Find the matrix A such that

A[ 1 0 ] = [ -5 -4]
[ -1 4] = [ 7 12]

hint: let A = [a b]
[c d]
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December 6th, 2010, 04:20 PM   #2
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Re: Help with Matrix problem

Do you know how to do matrix multiplication?


Set this equal to the given matrix,


then solve by setting corresponding elements equal to each other.
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December 6th, 2010, 04:33 PM   #3
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Re: Help with Matrix problem

Quote:
Originally Posted by The Chaz
Do you know how to do matrix multiplication?


Set this equal to the given matrix,


then solve by setting corresponding elements equal to each other.

I get to here:



Then:

In equation form is

a = -5 b= -4
-a + 4c = 7 -b +4d = 12

Solving for c and d gives

a = -5 b = -4
c = .5 d = d = 2

Is this correct?



I am new to this, just trying to figure it out by following along in a book.
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December 6th, 2010, 04:51 PM   #4
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Re: Help with Matrix problem

4b = -4
a - b = -5
4d = 12
c - d = 7
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December 6th, 2010, 05:10 PM   #5
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Re: Help with Matrix problem

Quote:
Originally Posted by littlebu

...I am new to this, just trying to figure it out by following along in a book.
You should follow along with my reply!
Compare the matrices in my reply with the statements in greg1313's post
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December 6th, 2010, 05:11 PM   #6
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Re: Help with Matrix problem

Hello, littlebu!

It would help if you didn't scatter your work . . .


Quote:





[color=beige]. . . . . . . . . . . [/color]







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December 6th, 2010, 06:13 PM   #7
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Re: Help with Matrix problem

Thanks for the replies everyone, this is really helpful and makes sense now. This forum is fantastic, it is hard to "teach" yourself from a book when you don't know what to do, thanks again for the help I have a feeling I am going to be asking a lot of questions here. Hope you all don't get annoyed with me lol.
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