On BART today, a fellow passenger saw me making notes on paper and occasionally looking up, and got the idea that I was taking statistics on the passengers. No, I said, I’m doing math for my own entertainment. He sat beside me and I explained it; he seemed to grasp more than I expected of a random layman. Finally he said, “But I still don’t see how the people come into it.”
The problem: to define
u(t) = Σ ak cos(kt), 0 ≤ k ≤ 3
so that
u(0) = u(π) = 0
u(α) = 1
u′(α) = 0.
I solved it – it’s simple enough – but it did not make me happy; what I really wanted was for 0,1 to be global extrema, and I don’t know how to do that efficiently. So I guess it’s back to Fourier series.
(Note to self: certain symbols do not render properly in Lucida Sans Italic.)
At a party this evening, an Indian named Rādhā was surprised when I asked, “Do you spell it with an h?” Years ago I used to go often to Country Station Sushi Café on Mission Street, near which there is or was a Hotel Radha whose sign has the name written in Nāgarī.