Crash when Solve for Integral with 15C

[Dieter]

(09-02-2017 01:40 PM)rprosperi Wrote:  Thanks Dieter. All this makes sense to me, as is so often the case, after the explanation. Though I initially would have guessed that the 15C would treat FIX 2 as 2 significant places,

Well, a tolerance of ±0,01 (FIX 2) means a relative error of 1E–6 for x=10000 while it's 1% for x=1. Or even 100% for x=0,01. This makes quite a difference. ;-)

(09-02-2017 01:40 PM)rprosperi Wrote:  Though subtle, this is a significant difference and highlights how the machine handles the numbers internally (vs. display) and so is an interesting exercise.

Actually the display format specifies the accuracy of the integrand, not the integral. That's another subtle difference, and you might want to read more about this in the 15C Advanced functions handbook and/or one of the other sources below.

(09-02-2017 01:40 PM)rprosperi Wrote:  I will read the referenced section in the 15C AF HB. Again! AFAIK, this is the best treatment of such topics in any HP manual; can you recommend others I may have missed?

Sure: first there is the original HP34C manual that discusses integration in detail. This refers to the original implementation which AFAIK was also used for the 15C. Then there is an article by W. Kahan in the August 1980 HP Journal issue where the new functions of the 34C (Solve and Integrate) are introduced and discussed.

Dieter