About
Mathwords
1. "Help! I can't remember and I don't know where to look it up."
This website is designed for math students who need an easytouse,
easytounderstand math resource all in one place. It is a comprehensive
listing of formulas and definitions from beginning algebra to calculus.
The explanations are
readable for average math students, and over a thousand illustrations
and examples are provided.
I have been a math teacher and tutor for high school and college
students since 1984. In my experience, only the most enthusiastic
and accomplished math students remember everything from earlier
coursework. Everyone else spends a lot of time feeling lost.
Existing math reference resources are no help for most math students.
Professional math reference guides are excellent for advanced
students and professionals. They are useless, however, for the
vast majority of math students. Authors of professional guides
are unforgiving in their use of technical language, so the definitions
are difficult to read.
Textbooks aren't much help, either. They usually have appendices
of formulas and/or glossaries, but these are an afterthought and
seldom are helpful. Often the topic a student wants to look up
is not covered because it is too elementary. Backofthebook glossaries
are usually terse, technical, and have no illustrations or examples.
They are only helpful to students who already know the material.
The arrangement and content of textbook appendices tends to discourage
average math students from using them.
2. How the definitions are written
Whenever possible, I tried to have the first words of each definition
describe the term precisely, accurately, and with a minimum of
jargon.
Denominator
The bottom part of a fraction. For ,
the denominator is 47.

Sometimes I could not meet this goal. I could write a precise
definition that was hard to follow, or a readable definition that
was imprecise. In such cases I gave both versions: the readable
definition first, then the precise one.
Ellipse
A conic section which is essentially a stretched circle.
Formally, an ellipse can be defined as follows: For two
given points, the foci, an ellipse is the locus of points
such that the sum of the distance to each focus is constant.

3. What
is not in this website
In order to keep the site to a manageable size, I decided early
on to exclude obscure specificpurpose formulas and techniques.
Such examples include the geometric technique of mass
points.
I also decided not to include much from the AP Statistics curriculum
or from discrete math. In order to keep the size of this already
large site manageable, I chose to limit the scope of mathwords
to course content from beginning algebra to calculus.
I did not include a comprehensive listing of postulates
and theorems from geometry. The "official list" varies somewhat
from text to text, so any overall listing would be of little practical
use. A large number of standard Geometry theorems are included,
and so is the parallel postulate.
Finally, Idecided to leave certain basic skills and terms
undefined. I omitted most basic arithmetic skills (e.g. multiplication
of integers, long division), and I decided not to define fundamental
terms such as "number".
I encourage
readers of this guide to contact
me with suggestions
for later editions. 