> Up through my first differential equations class I found almost everything trivial to learn
Mankind hasn't yet figured out a good way to teach the first Differential Equations course.
The first serious Calculus course introduces some level of rigor and formalism, but this alone is not sufficient for Diff Eqs. And the DE courses are typically leaning towards applications, so they tend to succumb to the "fiddle these dx's and dy's around like it's magic, in the end it might work out" approach.
The business is well founded, which you will discover later. But no one has figured out how to massage that into the first course.
It's been a while but I think this is true of a lot of introductory courses in general, like Organic Chemistry. "Trust us and memorize these rules the basis of which will become clearer down the road."
Mankind hasn't yet figured out a good way to teach the first Differential Equations course.
The first serious Calculus course introduces some level of rigor and formalism, but this alone is not sufficient for Diff Eqs. And the DE courses are typically leaning towards applications, so they tend to succumb to the "fiddle these dx's and dy's around like it's magic, in the end it might work out" approach.
The business is well founded, which you will discover later. But no one has figured out how to massage that into the first course.