“Young man, in mathematics you don't understand things. You just get used to them.” -- John Von Neumann
My approach to "understanding" (if that's the right word) the quaternions was to first memorise the various identities relating quaternion algebra to 3d rotations. I didn't actually "understand" them, and I still feel a bit dodgy with them, but I got used to them in a way. Second, it helps to try and solve some problems with them. That also gets you "used" to them.
The 3B1B videos are supplementary for me. I still find quaternions a bit miraculous. And Geometric Algebra doesn't seem like the solution for me, because it's another weird and even more complex formalism.
My approach to "understanding" (if that's the right word) the quaternions was to first memorise the various identities relating quaternion algebra to 3d rotations. I didn't actually "understand" them, and I still feel a bit dodgy with them, but I got used to them in a way. Second, it helps to try and solve some problems with them. That also gets you "used" to them.
The 3B1B videos are supplementary for me. I still find quaternions a bit miraculous. And Geometric Algebra doesn't seem like the solution for me, because it's another weird and even more complex formalism.