Aha, I figured it out. The issue is I'm trying to fit a portion of a sine
cycle to a Fourier sine series. Unless the cycle starts and ends at a zero,
the sine series is *not* a single term. (Instead it's a big mess that I
certainly do NOT intend to assign on a 50-minute test!) -Carl
(Sorry to be talking to myself. One disadvantage of digest mode is I don't
see the postings for a while. I'll probably see tomorrow that some of you
could have told me all this sooner. But I learned something important from
this exercise. Teachers and not just students can learn from tests!)