Contoh Program Metode Regulafalsi

uses crt;

label ulang;

var

x1,x2,x3,y1,y2,y3:real;

i:integer;

Ab:char;

data1:real;

begin

ulang:

clrscr;

write('tentukan nilai persamaan f(x)=x^3+x^2-3x-3=0 dengan regulafalsi');

write('masukan nilai x1');

readln(x1);

y1:=x1*x1*x1+x1*x1-3*x1-3;

writeln('nilai f(x)=',y1:0:4);

repeat

begin

write('asukan nilai x2=');

readln(x2);

y2:=x2*x2*x2+x2*x2-3*x2-3;

write('nilai f(x2)=',y2:0:4);

end;

if y1*y2 <0 then

writeln('syarat nilai OK!');

writeln('nilai x2 belum sesuai');

until y1*y2 <0;

writeln;

writeln('penyelesaiannya persamaan karakteristik dengan regulafalsi');

writeln('----------------------------------------------------------');

writeln(' n            X           f(x)            error           ');

writeln('----------------------------------------------------------');

repeat

begin

i:=i+1;x3:=(x2-(y2/(y2-y1))*(x2-x1));

y3:=x3*x3*x3+x3*x3-3*x3-3;

if y1*y2<0 then

writeln(' ',i,':',x3,':',y3,':',abs(y3),':');

writeln(' ',i,':',x3,':',y3,':',abs(y3),':');

if y1*y3 <0 then

begin

x2:=x3;y2:=y3;

end

else

begin

x1:=x3;y1:=y3;

end;

end;

until abs(y3)<1E-08;

writeln('------------------');

writeln('Akar persamaan=',x3);

writeln('errornya=',abs(y3));

writeln('------------------');

writeln('apakah anda ingin mengulang ?[y/t]');

readln (ab);

if (ab='y') or (ab='y') then

begin

goto ulang

end;

end.