Hi I'm planning to self study physics from University physics by Freedman so i have a couple of questions 1) how important is the Mastering physics package if the goal is to self-study? Could i make it without masterin physics? 2) Should i get the technology update edition? 3) What are the major differences between 12th and 13th edition? It seems to me that 12th edition is much cheaper, but I also want good explanations and a clear text so I'm not left wondering if i clearly understood the concept.