In 2009-2010, I will use Boas, Mathematical Methods in the Physical Sciences, for both Physics 104A and Physics 104C. For both classes you may use the third OR second edition. Apart from a slight reordering of the material, they are essentially identical. I will list the sections I cover in class and the assigned problem numbers for both editions. A full-price new third edition costs over $100, but most students find it a useful reference well beyond the end of the course. You can buy used third editions for less, and used second editions for a lot less. Happy shopping!