As the best-seller in its field, "Trigonometry, 5/e, offers both instructors and students a more solid, comprehensive, and flexible program than ever before. Designed for the one- or two-term precalculus course, the text introduces trigonometry first with a unit circle approach and then with the right triangle.For a complete listing of features, see Larson/Hostetler, "College Algebra, 5/e.
The book was clear enough on most concepts while the first exercises where simple enough and last complex enough.
The only thing bad about the book is that at some points the exercises didn't have enough material behind them to understand them clearly (usually they were the last few exercises) but a quick google search and or youtube video solved that. Also it had quite a few etymological questions that were not that clear.