Why no SOLVE & INTEGRATE commands on the 41C?

[hth]

Lots of good points are given above.

I want to add that it is highly likely that the HP-41 was originally budgeted for having a 16K OS as can be seen from the use of page 0-2, then 3 empty and 4 being the diagnostic ROM. Thus, they originally set aside 16K for the machine but in the end only used 12K, leaving page 3 unused (until the 41CX).

Most likely they thought the would need that space but perhaps found that they could get away with 12K if they dropped a few features. Given that the HP-41 is so versatile and expandable, they probably decided to step back a bit and saved a 40KBit ROM chip from being inserted into each produced HP-41 unit.

Fitting it into opcode table would not have been too hard, it has several rather dubious instructions, ADV, CLRG, DEC, OCT are good candidates to be left out. There are also a couple of unused slots, though I do not know how easy it would be to make use of them.