(35S) 2nd order Derivative (at a point)

[trojdor]

Thank you, kind sir.

(Interestingly, the rounding errors of the calculator seem to work in favor of the algorithms chosen.
When I use my 35s programs to solve the 4th deg problem for both f' and f", I get 328.000000000 and 270.000000000 respectively.)

You may also have convinced me that my other, center differencing program for the 1st derivative est. may have some practical value after all.
Rather than toss it out, I'll type it up and post it later.
It's pretty compact.

Thanks again for all the time/effort,
mike