If a serious undergraduate Theoretical Physicist, quickly speed through the basics in Boas Math Methods, then Morse + Hassani Methods+ Arfken will put you in  a fair standing. Avoid RileyHobbsBence Mathematical Methods like the plague. It is the most cumbersome and driest text I have ever encountered. Dehydrated reading a page of that. For Physicists, maths book guide is : Boas, Arken, Hassani (Math Methods), then Hassani (Math Foundations) then perhaps Morse. Avoid RHB! Ghastly book, overused in all UK universities.The only saving grace of RHB is its exercises are from old tripos exams, so cannot complain. Ghastly book otherwise.