From another place in the net, pointed to by J.F. Garnier:
Professor William Kahan describes his work on HP’s celebrated line of programmable calculators, squeezing highly efficient solve, integrate, and matrix functions into their severely limited hardware capabilities. Here's the video: https://www.youtube.com/watch?v=5mBw7tnRx1c.
Further links can be found here: https://retrocomputingforum.com/t/kahan ... 2236?u=eds. Enjoy!
About solve, integrate, and matrix operations
About solve, integrate, and matrix operations
WP43 SN00000, 34S, and 31S for obvious reasons; HP-35, 45, ..., 35S, 15CE, DM16L S/N# 00093, DM42β SN:00041