Matrix Algebra with Applications
Errata and brief additions to text

 As of Mar. 24, 2001
 As of Apr. 5, 2001
 As of Apr. 19, 2001

Start of Mar. 24, 2001 errata
1. p.3, line -10: Add "but distinct" after "two lines are parallel"
2. p.5, line -1: Add "or A=[a_ij]" before "to denote".
3. p.11, In COROLLARY, delete the word "different". It's not needed. (Of course then "a" must change to "an".)
4.  p.22, In (1),  after "x₃=...x₅" add ",  x₂, x₅ arbitrary"
5. p.23, In Figure 1.6 display, insert a line  ">> format rat" before the line ">>C".
6. p.28, line 9 and lines 15-16: I'd prefer it here and elsewhere if the alternatives "constrained" (for dependent) and "unconstrained"(for independent) were used when referring to variables. Later on the words "dependent" and "independent" will be used in a quite different way to refer to sets of vectors; it's helpful to keep from using the same words in two quite different ways.
7. p.29, In top display,  after "x₃ = ...x₆" add ", x₂ , x₄, x₆ arbitrary,"
8. p.48, In Solution to Example 2, line 2, after "- x₄ " and before "." add ", x₃ , x₄ arbitrary"
9. p.63, Definition 9 of A^T, l.2 has a major misprint: replace b_ij=a_ij by b_ij=a_ji
10. p.69, Problem 32. You could replace "|x₁ | + |x₂ | > 0" by the equivalent ""
11. p.101, In the display at the top replace x₁ by x₁. Similarly for x₂.
12. p.105, Sect 1.9, Problem 73, After (n x n) add "singular".
13. p.A20 (Answers), Ex 1.2, #3(a): Change "operation" to "operations", AND delete "R₂ - 4 R₁ ,".
14. p.A20 (Answers), Ex 1.2, #9: Change row 3, column 4 of matrix shown from 0 to 1.
15. p.A20 (Answers), Ex 1.2, #15: Delete the wrong answer and add "The system is inconsistent".
16. p.A20 (Answers), Ex 1.3, #3: The matrix given is only in echelon form, not the requested REF. The information derived from EF is the same as that from REF so far as this problem is concerned.
17. p.A21, 1.4.1(c) Answer is for version of problem in previous edition where range for x₁ was asked for. Ans. for (c): Range for x₄ : 200 <= x ₄ <= 600 .

Start of Apr. 5, 2001 errata
18. p.A21, The correction two items back, listed as p.A20, Ex.1.3, #3 should have been listed as occuring on p.A21. For the full corrections to get REF (which is not really needed to figure out what the Theorem 3 n,r,n-r values will be) you need to perform R₂ + R₃, R₁+R₃ to get 0's above the leading 1 in row 3 column 4. Then some additional steps to take care of the leading 1 in row 2 column 2. ALSO,
19. p.A21, Ex. 1.3, #1 answer has the same problem - EF is given when REF is asked for. Thus to have a correct REF the op R₁+(1/2)R₂ yields the correct top row: [1 1 0 5/6]. (Thanks to Laura Kogler for these two.)
20. p.A22, Ex. 1.5, #45 answer is slightly wrong: x₅ should multiply a vector (in R⁵ with 2nd row -1 instead of 1. (Thanks to Brian Tocco.)

Start of Apr. 19, 2001 errata
21. p.52, In example 5, in y₂= 3x₁... equation, change x to z to get y₂= 3z₁...(Thanks to Deb Crowe).
22. p.81, line 4 - the first display - change a₂t to a₂t², so there is a second power term in the correct spot. (Thanks to ?? )

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