brilliant.org has decent courses on linear algebra, including nodal analysis ($100/year or so). You don't need to know a lot; you do need to know how to express a linear equation as a matrix and solve with row reduction, and eventually, how to apply that to nodal analysis.
alcumus and AoPS textbooks are pretty adequate for rational functions, complex numbers, roots-of-unity, etc. You should know everything in their intermediate algebra and precalculus textbook (and ideally, their title textbooks: AoPS Volume 1 and 2). These aren't too long, are much more advanced than normal high school curricula, and are worth doing in either case, skipping the parts you know. Next step is something like MIT 6.302 OCW, which is brilliant.
For differential equations and Laplace, any differential equations textbook will be adequate. I would not do a deep dive here. A shallow one will more than suffice. If you kind-of-get-it, that's good enough.
If you lack calculus background for this dive, OSU MOOCulus or AoPS Calculus are good places to go. OSU will be easy, step-by-step, and AoPS will be challenging, so it depends on your background.
For most people, this takes 2-4 years, and you can't really cram it (which is both good and bad news; a little time each day is almost as good as learning full-time here; you can read about the spacing effect).
brilliant.org has decent courses on linear algebra, including nodal analysis ($100/year or so). You don't need to know a lot; you do need to know how to express a linear equation as a matrix and solve with row reduction, and eventually, how to apply that to nodal analysis.
alcumus and AoPS textbooks are pretty adequate for rational functions, complex numbers, roots-of-unity, etc. You should know everything in their intermediate algebra and precalculus textbook (and ideally, their title textbooks: AoPS Volume 1 and 2). These aren't too long, are much more advanced than normal high school curricula, and are worth doing in either case, skipping the parts you know. Next step is something like MIT 6.302 OCW, which is brilliant.
For differential equations and Laplace, any differential equations textbook will be adequate. I would not do a deep dive here. A shallow one will more than suffice. If you kind-of-get-it, that's good enough.
If you lack calculus background for this dive, OSU MOOCulus or AoPS Calculus are good places to go. OSU will be easy, step-by-step, and AoPS will be challenging, so it depends on your background.
For most people, this takes 2-4 years, and you can't really cram it (which is both good and bad news; a little time each day is almost as good as learning full-time here; you can read about the spacing effect).