I am an Mechanical Engineering major and just recently I found myself to be very interested in Computational Mathematics. I have taken the typical 3 courses on Calculus but the problem is that since they were being taught majorly to an engineering audience, no one bothered with the epsilon deltas. I know how to find limits, differentiate weird functions and integrate improper integrals but when I try to read research on Nonlinear Optimization or Numerical Linear Algebra, I am unable to follow the math because of its rigor. I have some time to work on this before joining graduate school and wanted a recommendation for a good book that would allow me to revise the 3 semesters of calculus while simultaneously improve my ability to read and write rigorous proofs. However, I don't want a book like Apostol or Spivak (which run for thousands of pages) because I already know a lot of Calculus and honestly, it gets boring. My goal is to finish revision and introduction of rigor as quickly as possible and move on to more advanced stuff that I am currently stuck on (Boundary Value Problems in Fluid Mechanics, NLA and Optimization to name a few) I already have Apostol and Kenneth Ross but the former is tooooooo long and the latter (I believe) stops abruptly. Any suggestions?