HP-41 Challenge: Double Integrals by INTEG Recursion

[Ángel Martin]

(06-01-2016 04:12 AM)Valentin Albillo Wrote:  

(05-31-2016 04:52 PM)gjmcclure Wrote:  With f(x,y,z,u,w) = sqrt(6-x^2-y^2-z^2-u^2-w^2) evaluate
integ(0,0.7) [ integ(0,0.8) [ integ(0,0.9) [ integ(0,1.0) [ integ(0,1.1) f(x,y,z,u,w) dw ]
du ] dz ] dy ] dx. The answer seems to lie around 1.189.

This quintuple integral is easy as pie for the HP-71B w/Math ROM using straight out-of-the-box code with no fancy programming or buffer juggling needed.

Glad this thread pulled you in from your greener pastures Valentín, always a pleasure to read your comments. Sure enough the 71B/MathPac is a vastly superior engine and the recursion functionality there is impressive - yet for a much humbler platform like the 41's the "buffer juggling" is a very elegant work-around - notwithstanding its inherent design limitations of course.

Saludos,
ÁM