Need Help! Alguien que la tenga mas o menos clara con Delphi??

[MARS]

Basicamente lo que necesito es ingresar una funcion mediante un TEdit.

Digamos, Asquerosamente a lo bruto, algo asi:

function func(x):double;
begin
func:=Form1.Edit1.Text;
end;

Donde Edit1.Text sea por ejemplo: (exp(-x))-x;

me estoy rompiendo el mate con eso hace horas, y encima supongo que debe ser una gilada de aquellas.

btw, para el curioso, el programa es de Busqueda de Raices por Biseccion, Regula Falsi, Punto Fijo, Newton Raphson con tabla de iteraciones detallada, etc, funca todo, lo unico q me falta para dejarlo pipi cucu es eso xD

Por si a alguien le interesa el .pas

unit AN;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, DBTables, Grids, DBGrids, ComCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    TabSheet4: TTabSheet;
    TabSheet5: TTabSheet;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    Table1: TTable;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Edit5: TEdit;
    Button1: TButton;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Edit6: TEdit;
    Edit7: TEdit;
    Edit8: TEdit;
    Edit9: TEdit;
    Edit10: TEdit;
    Label16: TLabel;
    TabSheet3: TTabSheet;
    Label6: TLabel;
    Label7: TLabel;
    Label8: TLabel;
    Label9: TLabel;
    Label10: TLabel;
    DBGrid2: TDBGrid;
    DataSource2: TDataSource;
    Table2: TTable;
    Button2: TButton;
    DataSource3: TDataSource;
    Table3: TTable;
    DBGrid3: TDBGrid;
    Edit11: TEdit;
    Edit12: TEdit;
    Edit13: TEdit;
    Edit14: TEdit;
    Label11: TLabel;
    Label12: TLabel;
    Label13: TLabel;
    Label14: TLabel;
    Button3: TButton;
    DBGrid4: TDBGrid;
    Table4: TTable;
    DataSource4: TDataSource;
    Edit15: TEdit;
    Edit16: TEdit;
    Edit17: TEdit;
    Edit18: TEdit;
    Label15: TLabel;
    Label17: TLabel;
    Label18: TLabel;
    Label19: TLabel;
    Button4: TButton;
    Edit19: TEdit;
    Edit20: TEdit;
    Edit21: TEdit;
    Edit22: TEdit;
    Label20: TLabel;
    Label21: TLabel;
    Label22: TLabel;
    Label23: TLabel;
    DBGrid5: TDBGrid;
    DataSource5: TDataSource;
    Table5: TTable;
    Button5: TButton;
    Edit23: TEdit;
    Label24: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  var xl,xu,es,imax,iter:double;
  var xr,ea,xrold,test:double;
  var x:double;
  var aux:double;

implementation

function func(x:double):double;
//var aux:double;
begin

func:= (exp(-x))-x;

end;

function deriv(x:double):double;
begin

deriv:=(-exp(-x))-1;

end;

function xpunto(x:double):double;
begin
xpunto:=exp(-x);
end;

function bisect(xl,xu,es,imax:double):double;
begin

iter:=0;
ea:=1;
while (ea > es) and (iter <= imax)
do
begin

form1.Table1.Append;
form1.Table1.FieldByName('ITER').AsFloat := iter;
form1.table1.FieldByName('AI').AsFloat := xl;
form1.table1.FieldByName('BI').AsFloat := xu;
form1.table1.FieldByName('FA').AsFloat := func(xl);
form1.table1.FieldByName('FB').AsFloat := func(xu);

xrold:=xr;
xr:= (xl+xu)/2;

form1.table1.FieldByName('RI').AsFloat := xr;
form1.table1.FieldByName('FRI').AsFloat := func(xr);

iter:=iter+1;
if (func(xr) <> 0) then
begin
aux:=(xr-xrold)/xr;

ea:= abs(aux);

form1.table1.FieldByName('EI').AsFloat := ea;

end;
test:=func(xl) * func(xr);

if (test<0) then
begin
xu:=xr;

end
else if (test>0) then
begin
xl:=xr;

form1.Table1.Post;
end
else
begin
ea:=0;
end;
end;
bisect:=xr;
end;


function interp(xl,xu,es,imax:double):double;
begin

iter:=0;
ea:=1;
while (ea > es) and (iter <= imax)
do
begin

form1.Table2.Append;
form1.Table2.FieldByName('ITER').AsFloat := iter;
form1.table2.FieldByName('AI').AsFloat := xl;
form1.table2.FieldByName('BI').AsFloat := xu;
form1.table2.FieldByName('FA').AsFloat := func(xl);
form1.table2.FieldByName('FB').AsFloat := func(xu);

xrold:=xr;
xr:= xu-((func(xu)*(xu-xl))/(func(xu)-func(xl)));

form1.table2.FieldByName('RI').AsFloat := xr;
form1.table2.FieldByName('FRI').AsFloat := func(xr);

iter:=iter+1;
if (func(xr) <> 0) then
begin
aux:=(xr-xrold)/xr;

ea:= abs(aux);

form1.table2.FieldByName('EI').AsFloat := ea;

end;
test:=func(xl) * func(xr);


if (test<0) then
begin
xu:=xr;

end
else if (test>0) then
begin
xl:=xr;

form1.Table2.Post;
end
else
begin
ea:=0;
end;
end;
interp:=xr;
end;

function newton(xl,es,imax:double):double;
begin

iter:=0;
ea:=1;

while (ea > es) and (iter <= imax)
do
begin

form1.Table3.Append;
form1.Table3.FieldByName('ITER').AsFloat := iter;
form1.table3.FieldByName('XI').AsFloat := xl;
form1.table3.FieldByName('FXI').AsFloat := func(xl);

xrold:=xr;
xr:= -(func(xl)/deriv(xl))+xl;

form1.table3.FieldByName('XR').AsFloat := xr;
form1.table3.FieldByName('FXR').AsFloat := func(xr);

iter:=iter+1;
if (func(xr) <> 0) then
begin
aux:=(xr-xl)/xr;

ea:= abs(aux);

form1.table3.FieldByName('EI').AsFloat := ea;

end;
xl:=xr;
form1.Table3.Post;

end;
newton:=xr;
end;

function punto(xl,es,imax:double):double;
begin

iter:=0;
ea:=1;

while (ea > es) and (iter <= imax)
do
begin

form1.Table4.Append;
form1.Table4.FieldByName('ITER').AsFloat := iter;
form1.table4.FieldByName('XI').AsFloat := xl;
form1.table4.FieldByName('FXI').AsFloat := func(xl);

xrold:=xr;
xr:= xpunto(xl);

form1.table4.FieldByName('XR').AsFloat := xr;
form1.table4.FieldByName('FXR').AsFloat := func(xr);

iter:=iter+1;
if (func(xr) <> 0) then
begin
aux:=(xr-xl)/xr;

ea:= abs(aux);

form1.table4.FieldByName('EI').AsFloat := ea;

end;
xl:=xr;
form1.Table4.Post;

end;
punto:=xr;
end;


{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
while(form1.Table1.Bof = false) do
        form1.Table1.Prior;
While(form1.Table1.IsEmpty<>true)do
        form1.Table1.Delete;
xl := StrToFloat(edit1.Text);
xu := StrToFloat(edit2.Text);
es := StrToFloat(edit3.Text);
imax := StrToFloat(edit4.Text);

if (abs(xl)=abs(xu))
then
MessageDlg('El resultado de Xl + Xu tiene que ser diferente de 0',mtError,[mbOk],0)
else

Edit5.Text := FloatToStr(bisect(xl,xu,es,imax));

end;

procedure TForm1.Button2Click(Sender: TObject);
begin
while(form1.Table2.Bof = false) do
        form1.Table2.Prior;
While(form1.Table2.IsEmpty<>true)do
        form1.Table2.Delete;
xl := StrToFloat(edit6.Text);
xu := StrToFloat(edit7.Text);
es := StrToFloat(edit8.Text);
imax := StrToFloat(edit9.Text);

Edit10.Text := FloatToStr(interp(xl,xu,es,imax));

end;

procedure TForm1.Button3Click(Sender: TObject);
begin
while(form1.Table3.Bof = false) do
        form1.Table3.Prior;
While(form1.Table3.IsEmpty<>true)do
        form1.Table3.Delete;
xl := StrToFloat(edit11.Text);
es := StrToFloat(edit12.Text);
imax := StrToFloat(edit13.Text);

Edit14.Text := FloatToStr(newton(xl,es,imax));

end;

procedure TForm1.Button4Click(Sender: TObject);
begin
while(form1.Table4.Bof = false) do
        form1.Table4.Prior;
While(form1.Table4.IsEmpty<>true)do
        form1.Table4.Delete;
xl := StrToFloat(edit15.Text);
es := StrToFloat(edit16.Text);
imax := StrToFloat(edit17.Text);

Edit18.Text := FloatToStr(punto(xl,es,imax));

end;

end.