My new 17BII+ has just arrived. To make a long story short: I'm not impressed!

The device looks nice, the display is quite good, better then the 17BII. Keyboard feeling would be OK, if it didn't miss keystrokes! I have to poke beyond the point of tactile feedback to make sure that some keys register. This is a real nuisance! :-(

OK, I thougth, probably a bad sample, let's try to live with it and explore the new thing a little further.

The new calculator has more memory then the original 17BII, 32 KB instead of 8. Without a means of storing solver equations or data on an external device, and given the less then perfect alpha entry method, chances are good that you never want to fill up the additional memory space.

I've implemented the "well known" arc length integration problem as a solver equation:

1.) Create a list "CO" with coefficients 3/4, 9/8 and 9/8.

2.) Equation:

INT=L(H:X/L(M:3*N))**Sigma*(I:0:G(M):1:IF(I=0 OR I=G(M):3/8:ITEM(CO:MOD(I:3)+1))***SQRT(1+4*SQ(I*G(H)))**)

The equation is a numerical integration ("3/8 rule") applied to N subintervals. For N=1, the integrand (in bold) is evaluated at 4 points, generally at 3*N+1 points.

You can now enter N, the right hand side (6 in the original example) and solve for X.

The old 17BII is much faster than the new one: With a starting value of 2.0000 (disp 4), and N=4, solving for X took 45 seconds on the new calculator and just 15 seconds on the old one.

HP what did you do?

*Edited: 21 Mar 2008, 8:27 a.m. after one or more responses were posted*