HP42s first major program (Double Integral) Best way to approach?

[Werner]

Well, you could key in the program I supplied before, the post before Albert's.
Or you could use this, and use it interactively:

Code:

00 { 98-Byte Prgm }
01▸LBL "BORE"
02 MVAR "A"
03 MVAR "B"
04 MVAR "C"
05 1ᴇ-5
06 STO "ACC"
07 CLX
08 STO "LLIM"
09 PGMINT "FX"
10▸LBL 10
11 VARMENU "BORE"
12 STOP
13 RCL "C"
14 STO "ULIM"
15 INTEG "X"
16 4
17 ×
18 GTO 10
19▸LBL "FX"
20 RCL "B"
21 XEQ 01
22 RCL "A"
23 XEQ 01
24 -
25 RCL "C"
26 XEQ 01
27 ×
28 RTN
29▸LBL 01
30 X↑2
31 RCL "X"
32 X↑2
33 -
34 SQRT
35 END

To use, XEQ "BORE".
Enter the values for A, B and C (just enter a value and press the corresponding key), then press R/S. Reply is near instantaneous on a DM42.
You can enter new values - the previous ones are still there so you can just enter the ones that have changed, press R/S for the result.
Press EXIT to.. EXIT ;-)

It would help if you could transfer the file to your DM42, that would save you the trouble of keying it in. Just copy and paste the code into swissmicro's encoder page and upload the .raw file.

Cheers, Werner