Unformatted text preview: 3. Add a Multiple of a Row to Another Row. In this operation we will replace row i with
the sum of row i and a constant, c, times row j. The notation we’ll use for this operation
is Ri + cR j ® Ri . To perform this operation we will take an entry from row i and add to
it c times the corresponding entry from row j and put the result back into row i. Here is
an example of this operation. 3
é 1 -2
é 1 -2
ú R3 - 4 R1 ® R3 ê 2
ê -3 2 -2 -10 ú
ê -7 10 -14 -38ú
Let’s go through the individual computation to make sure you followed this. -3 - 4 (1) = -7 2 - 4 ( -2 ) = 10
-2 - 4 ( 3) = -14
-10 - 4 ( 7 ) = -38
Be very careful with signs here. We will be doing these computations in our head for the
most part and it is very easy to get signs mixed up and add one in that doesn’t belong or
lose one that should be there.
It is very important that you can do this operation as this operation is the one that we will
be using more than the other two combined.
Okay, so how do we use augmented matrices and row operation...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.
- Spring '12