How to set up homework:
- possibly include some in running text
  (better in more advanced, i.e., post-calculus books)
3 kinds at end:
- rote
  (do these until they're immediate...then do 2 more)
  basical computational skills: do "enough"
- core "thinking" questions
  un-important questions, but require thinking to solve
  roughly, "rote non-calculations"
- important results
  propositions/theorems that you -should- work through
  (results useful later: things that should be remembered,
   things that will be refered to later)
- fun topics
  not key/important results for later, but interesting and good to
  work through (e.g., hyperbolic functions)

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make solutions available, but make hints -more- available
(writing good hints is work: it's -additional- work on top of solving
the problem)
