Trouble with Inverse Matrices - Can You Help?

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    Inverse Matrices
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The discussion revolves around difficulties with inverse matrices and their multiplication with an identity matrix. The user has attempted to find the inverse of a given matrix but is struggling to make sense of the results. They suggest that performing row operations to achieve an identity format for the first five columns may clarify the situation. There is uncertainty about whether the goal is to find the norm of specific columns, indicating a lack of clarity in the original question. Direct calculations and using a semi-identity matrix are recommended to simplify the process.
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Homework Statement


21lpjs3.jpg


Homework Equations


I think it may have to do with inverse matrices or multiplication using the identity matrix

The Attempt at a Solution



I got the inverse of...

1,-2, 2, 2,-3
3,-5, 6, 2,-4
2,-2, 5,-4, 4
1,-3, 1, 7,-8
3,-4, 7, 0, 2

as...

-6,-14,25,20,-7
2,-13,19,14,-5
4, -2, 1, 0, 0
0, -1, 1, 1, 0
-1, 2 ,-3,-2, 1

and I premultiplied that to...

87, 57, 10,117,-101
208,232,133,330,-146
83,297,235,229, 116
154,-58,-97,112,-245
240,382,278,370, 092

But nothing really seems to make sense. Thanks if you can help!
 
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It looks to me like it's one big giant matrix and you'd have to do the row operations to get the first 5 columns in the identity format and see what that does to the last 5 columns.
Are you looking for the norm of columns 6-10? The question isn't entirely clear to me.
 
Last edited:
Yes, you have to do raw, direct calculations. But the semi-identity matrix will make it easier
 

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