These are things that one should know from high school or things that usually are not covered in a typical calculus course but they are needed anyway, it is assumed that a student would somehow pick them up along the way.
This part is just supplementary, definitely do not expect to see things like Methods Survey
or Exercises that you expect from "real" chapters. Unfortunately, I do not have time for
a full-scale chapter teaching the reader how to work with functions of more variables,
the aim of this text is to introduce basic geometrical concepts of multi-dimensional world.
I do it with the hope that it will help the reader when the time comes to learn functions
of more variables from textbooks.
In particular, do not expect to find here topics like transformation of variables in an integral, Green's theorem and similar topics. Perhaps when I have time...
Functions of more variables