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Liu Yongliang
Liu Yongliang

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Elementary Row Operations - [Linear Algebra #1]

Opening statement

So here I am, taking MA1101R Linear Algebra I - a required Math module for Computer Science undergraduate course at the National University Of Singapore. To make things slightly more interesting, I am going to try to make as many visualizations as I see fit, to demonstrate some of the concepts taught in lessons. This way, I guess I could say that Math is, in fact, useful to a web developer.

What's the use of Elementary Row Operations (ERO)?

  • Two augmented matrices are row equivalent if one can be obtained from the other by a series of ERO.
  • Two row equivalent augmented matrices have the same solution.
  • By transforming an augmented matrix to its Row-Echelon Form or Reduced Row-Echelon Form through Gaussian Elimination and Gauss-Jordan Elimination respectively, we can find out its solution.
Comparison Observation in REF Solution
More variables than equations There is a non-pivot column in the REF, other than the last column Infinitely many
Same number of variables and equations Every column of REF is a pivot column, except the last Only one
Inconsistent system Has a row with nonzero last entry but zero elsewhere, or the last column is a pivot column None

A quick demo of elementary row operations

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