More Typos (TF appendix)

Thanks to Amy Subert for this one:

In case anyone else was perplexed... there are two other typos in the T&F appendix you posted, as well (although one is corrected in the 5th edition of the book).

1. On page 914 of the posted version, equation A.13, in X13 it should be "bf-ce" not "bf-cd." This is corrected in the 5th edition of the book.

2. On page 914 of the posted version, and page 930 in the 5th edition, the value of X12 in the inverse of A should be POSITIVE 1.33 not "-1.33." Just a tiny error but it makes a big difference when "testing" the inverse.