Missing function on HP 42S

11172021, 06:51 PM
Post: #1




Missing function on HP 42S
I used to think that the lack of an Nroot key on the HP 42S was a bit of a shortcoming, especially if one wanted to integrate an equation that had fractional powers involved where negative numbers were involved. It would be a convenience to have such a key on the HP 42S, but it is not a hard work around…it is easy to break such an integral into 2 integrals. In the case of the negative part of the integral’s domain in an odd numbered root, to make that part of the integral produce a negative number, integrate it from the absolute value of the lower end of the domain as lower limit, and use 0 as the upper limit. Store the result. The domain from 0 on up can be integrated in normal fashion. This can then be added to the stored result for the answer to the full domain integral.
Carry on… 

11212021, 11:20 PM
Post: #2




RE: Missing function on HP 42S
(11172021 06:51 PM)lrdheat Wrote: ... it is not a hard work around…it is easy to break such an integral into 2 integrals. I think you have said very elegantly exactly why there is NOT an builtin function that does this, especially for something that does not come up very frequently. I would say the same about my own desires for a PMOD Modular exponentiation function. It's fairly easy to write a program that does this, and probably most people wouldn't use it anyway, hence there is no need to include it. (Never mind that ternary operators are tricky with a 4level RPN stack.) More functions == more opportunity for bugs, more development expense, more ROM, longer manual, longer time to market, etc. 99.999% of the time I like the 42s exactly how it is. Though, I do wish the CATalog function of the 42S was sticky and opened where you last exited. For example, having to enter MOD twice near each other in a program requires many keystrokes. 17bii  32s  32sii  41c  41cv  41cx  42s  48g  48g+  48gx  50g  30b 

11222021, 08:01 AM
Post: #3




RE: Missing function on HP 42S
(11212021 11:20 PM)Allen Wrote: I would say the same about my own desires for a PMOD Modular exponentiation function. Here's my 41compatible, stackonly version: Z^YMOD. Quote:Though, I do wish the CATalog function of the 42S was sticky and opened where you last exited. For example, having to enter MOD twice near each other in a program requires many keystrokes. You can make any builtin menu 'sticky' selecting it twice. To enter MOD twice, do SHIFTCONVERT SHIFTCONVERT again V (down) MOD (the menu doesn't go away) MOD Cheers, Werner 41CV†,42S,48GX,49G,DM42,DM41X,17BII,15CE,DM15L,12C,16CE 

11222021, 03:20 PM
Post: #4




RE: Missing function on HP 42S
I also find that assigning a function of interest to the custom menu is a good option!


11232021, 03:27 AM
Post: #5




RE: Missing function on HP 42S
(11222021 08:01 AM)Werner Wrote:(11212021 11:20 PM)Allen Wrote: I would say the same about my own desires for a PMOD Modular exponentiation function.Here's my 41compatible, stackonly version: Z^YMOD. Warner, Thank you for the menu tip! I did write my own 39 byte program (with 4 char label), but use storage registers: Code:
17bii  32s  32sii  41c  41cv  41cx  42s  48g  48g+  48gx  50g  30b 

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