I second that. Also recommend this course by Gilbert Strang @ MIT: https://ocw.mit.edu/courses/res-18-009-learn-differential-equations-up-close-with-gilbert-s

I second that. Also recommend this course by Gilbert Strang @ MIT: https://ocw.mit.edu/courses/res-18-009-learn-differential-equations-up-close-with-gilbert-strang-and-cleve-moler-fall-2015/ https://ocw.mit.edu/courses/res-18-009-learn-differential-eq... https://www.youtube.com/playlist?list=PLUl4u3cNGP63oTpyxCMLKt_JmB0WtSZfG https://www.youtube.com/playlist?list=PLUl4u3cNGP63oTpyxCMLK...