Hello all, I'm a Senior in undergrad physics. I want to teach my sister physics as well as prepare for the GRE this summer. What are solid introductions both mathematically and conceptually concise? I am thinking of Physics: Concepts and Connections (5th Edition) by Art Hobson before I start a rigorous math introduction. Has anyone any opinion on this book? I can't seem to find it in any library near me, and I'm wondering if it is worth buying. Specifically, does it properly explain the concept of fields (E&M) and why we use them and minimization principle? I plan on using griffiths/taylor for more math-oriented introductions. Are there any online lectures better than these? Taylor is excellent, but I always found Griffths inconsistent in his flow between concepts. Any help would be greatly appreciated, thank you!