Help: Plotting points through a 39gii Program - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: Help: Plotting points through a 39gii Program (/thread-233599.html) Help: Plotting points through a 39gii Program - Eddie W. Shore - 11-04-2012 I am attempting a plot where: x axis: x_1 and y axis: f(x_1) where x_k is determined by: x_1 = x_0 - f(x_0)/f'(x_0) (Newton's Method) So far my program is: NEWTPATH(t,n) BEGIN LOCAL k,w,y; RECT(); FOR k FROM 1 TO n DO t-(F1(t)/der(F1(X),X=t))- > w; F1(w)- > y; PIXON(w,y); w- > t; END; FREEZE; END; The "der" is the derivative funtion. The program either freezes at the input screen or gives me an "out of bounds" error. I have F1(X) already stored before running the program. Any ideas? Thanks! Eddie Edited: 4 Nov 2012, 11:43 a.m. Re: Help: Plotting points through a 39gii Program - Bunuel66 - 11-04-2012 Have you checked that the derivative is never going null? Just my 2 cents... Re: Help: Plotting points through a 39gii Program - Eddie W. Shore - 11-04-2012 I am not sure. When I tried debugging the program the calcualtor goes into "space" when it approaches the loop. Apparently, der(F1(X),X=t) isn't allowed in a program. I think this is what you meant by the derivative being null. Really dumb not to allow calculus functions. This is what I have now: NEWTPATH(g,n) BEGIN LOCAL k,w,y,h,d,X; RECT(); FOR k FROM 1 TO n DO F1(g)->h; der(F1(X),X=g)->d; t-h/d->w; F1(w)->y; PRINT(w); w->t; END; END; Now I get a syntax error on Line 8 every time. Even if I change the der(F1(X),X=g)->d to 1->d, I still get this error. I have no idea where I have the syntax error, I localized all the varaibles, including X. Edited: 4 Nov 2012, 1:56 p.m.