# KIM MALTMAN'S MINI-COURSE ON TRIG BASICS

## CHAPTER 1, SECTION B: BASIC CONVENTIONS FOR ANGLES AND ANGULAR MEASURE

OVERVIEW:

This section of Chapter 1 discusses the basic conventions used in assigning number (angles) to directions in the xy-plane. The main points for discussion are:

• To what direction do we assign the value 0 for the angle?

• What is the geometric meaning of a positive or negative value of the angle?

• How are the common units for measuring angles (radians and degrees) defined, and how do we (i) actually go about associating an angle to any given physical direction and (ii) given an angle in degrees or radians, actually go about figuring out what direction it corresponds to?

If you do not yet feel comfortable with the idea of what an angle is, and how it used to specify directions in the plane, you might want to first briefly read (or re-read) Section (a), of Chapter 1 of the course (which gives some motivation for why we might want to assign numbers (angles) to directions in the plane). The terminology "first quadrant", "second quadrant", "third quadrant" and "fourth quadrant", used to specify whether a direction is up or down and to the left or right in the xy-plane, is also introduced in this section. Since this terminology will be used extensively in the rest of the course, you should also make sure you are familiar with it before going on.

If you are already familar with this background information, you can proceed directly to the contents of the current section of the course by clicking HERE.

CLICK HERE FOR TO SEE THE ANSWERS TO THE EXERCISES FOR ALL SECTIONS OF CHAPTER 1 INCLUDING THIS SECTION