Re: HP71B Maths Module Message #11 Posted by Valentin Albillo on 3 May 2012, 7:33 a.m., in response to message #10 by John Abbott (S. Africa)
Quote:
Thanks Valentin, I have previously read all your articles and find them, and your previous challenges fascinating. Yes I am into Math, Engineering, Stats and physics and while the HP71 is a great machine, the Math Rom is a must as I see it. So I will keep looking.
Thanks to you for your kind words and interest in my humble HPrelated productions and I wish you the best of lucks in getting the Math ROM. When you eventually do, which I'm sure you will, you can try it with the following textbooklike problem, which is solved quickly and effortlessly:
"The region R between the spheres of radius 4 and 5 is filled with a material whose density is given by D(x,y,z)=1+x^{2}+y^{2}.
Find the mass of this region."
My quick'n'dirty 4line HP71B + Math ROM solution is:
10 DEF FNF(Z,F,R)=(1+(R*SIN(F))^2)*R*R*SIN(F)
20 DEF FNG(X,Y)=INTEGRAL(4,5,P,FNF(X,Y,IVAR))
30 DEF FNH(X)=INTEGRAL(0,PI,P,FNG(X,IVAR))
40 RADIANS @ P=1E7 @ DISP INTEGRAL(0,2*PI,P,FNH(IVAR))
>RUN
3775.77549092
>CALL IDENTIFY(IVALUE,S$) @ S$
18028/15*Pi
where IDENTIFY is the parameterless invocation of my constant recognition subprogram as featured in one of my articles, namely Boldly Going  Identifying Constants downloadable from the link I previously gave.
So, as you can see, a complicated tripleintegral problem is numerically solved in just 4 lines of simple Math ROM code, plus full symbolic recognition available as well if needed. What more can one ask for ? ... :D
Regards from V.
