MATH221 December 2007
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Find the inverse of the matrix
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We are going to use Gauss-Jordan elimination. Append the identity matrix to B,
and proceed to row-reduce.
First, we multiply the first row by 1/2.
Second, eliminate the 3 and 5 entries in the third row by subtracting 3 times the second row from the third, and subtracting 5 times the fourth row from the third.
After these steps, we obtain
The last step is to add the third row to the first row. We find
Therefore, by Gauss-Jordan elimination, we have found
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