How to evaluate a function in a given point - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: How to evaluate a function in a given point (/thread-13761.html) How to evaluate a function in a given point - ailoher - 10-05-2019 02:54 PM Hello everyone, I have just acquired my HP Prime, and this weekend I decided to spend some time learning how to implement some basic numeric methods on it. While doing so with Regula Falsi, despite my code is apparently correct, I am continuously being given the message 'Incorrect argument type' when running it on my device. You can find it attached below: EXPORT REGULA_FALSI() BEGIN LOCAL n,a,b,xnew,tol,N,f; N := 100; tol := .001; IF INPUT( {{f,[8]},{a,[0]},{b,[0]},{tol,[0]},{N,[0,1]}}, "Regula falsi's method", {"f(X)=", "Left guess=", "Right guess=", "Tolerance=", "Max iter.="}, { "Enter the function surrounded by single quotes", "Enter the initial left guess", "Enter the initial right guess", "Enter the tolerance", "Enter the maximum number of iterations" }, {f,a,b,tol,N} ) THEN F0 := expr(f); L1 := {}; L1(1) := a; FOR n from 2 to N+1 DO xnew := a - F0(a)*(b-a)/(F0(b)-F0(a)); IF F0(a)*F0(xnew) < 0 THEN b := xnew; ELSE a := xnew; END; L1(n) := xnew; IF F0(a) < tol THEN BREAK; END; END; editlist(L1); END; END; Do you have any clue about why isn't it correct? Thank you so much in a advance, and may you have a nice day. With kind regards, Aitor RE: How to evaluate a function in a given point - Tyann - 10-06-2019 06:06 AM Bonjour Le problème semble venir de F0 qui si j'ai bien compris doit contenir la fonction entrée dans f. Je vous propose les modifications suivantes : IF INPUT({f,[8]},..... <-> IF INPUT({f,[2]},...... F0:=expr(f); <-> F0:=f; Suite à ces corrections je n'obtiens plus d'erreur d'argument. Espérant avoir pu vous aider. Hello The problem seems to come from F0 which if I understood correctly must contain the function entered in f. I propose the following changes: IF INPUT({f,[8]},..... <-> IF INPUT({f,[2]},...... F0:=expr(f); <-> F0:=f; Following these corrections I no longer get an argument error. Hoping to have been able to help you.