Fundamentals of Differential Equations (5th Edition)
R. Kent Nagle, Edward B. Saff, Arthur David Snider
This textbook lacks clear examples, explanations, and relevant homework problems. It will bog you down in lines of computations without adequate context. I don't recommend using this book, especially if you are trying to learn the material on your own. If you have to use it for a class, you have my empathy.
