We have tried to make this edition of Trigonometry useful to students in a variety of programs. For
example, students who have encountered elements of triangle trig in previous courses may be able
to skip all or part of Chapters 1 through 3. Students preparing for technical courses may not need
much of the material after Chapter 6 or 7. Chapters 9 and 10 cover vectors and polar coordinates,
optional topics that occur in some trigonometry courses but are often reserved for precalculus.