I've read and studied a lot of undergraduate math and scientific books, and this is probably the worst piece of crap I've ever (unfortunately) stumbled by. By any means, if you are taking a numerical methods course, do not use this book. It's lazy, it's poorly explained and confusing. A lot of useless and absolute dogshit exercises. If you have the opportunity of NOT opening this book (it wasn't my case since it was the bibliography of a subject I took), do NOT open it.