Double factorial [wp34s]

[Gerson W. Barbosa]

(02-13-2016 10:41 PM)Paul Dale Wrote:  

(02-12-2016 10:33 PM)Paul Dale Wrote:  The manual doesn't number the constants, instead the has user to count them. It also stops the documentation at the final user constant.

Walter corrected me, I was wrong here too. The manual does list the extra constants and it does number them.

Speaking of factorials and constants, I've found quite by chance a remarkable approximation to a Gamma-related constant (13 SD!). It's the positive real root of the polynomial equation x^28 + x^27 + x^26 + ... + x^4 + x^3 + x^2 - 130615 = 0. I think the wp34s solver can handle that, but it might be easier to check this on the hp 50g:

Code:


« [ 1 ] { 29 } RDM 1 CON 28 [ 0 -130615 ] REPL PROOT 6 GET C→R DROP
»

The four rising and falling factorials functions have been naively implemented. They might overflow when they shouldn't, like some comb and perm functions in some old calculators.

Thanks, Walter, for helping. I haven't found my copy of the Blue Book yet, but at least I've found my spare wp34s with good batteries in it :-)

Gerson.