Código Scilab – Método de la Regla Falsa

function y=f(x)
y=exp(-x)-log(x);
endfunction


function xr=reglafalsa(xai,xbi,tol)
i=1;
ea(1)=100;
if f(xai)*f(xbi) < 0
    xa(1)=xai;
    xb(1)=xbi;
    xr(1)=xa(1)-f(xa(1))*(xb(1)-xa(1))/(f(xb(1))-f(xa(1)));
    printf('It.              Xa           Xr            Xb            Error aprox \%\n');
    printf('%2d \t %11.7f \t %11.7f \t %11.7f \n',i,xa(i),xr(i),xb(i));
    while abs(ea(i))>=tol,
      if f(xa(i))*f(xr(i))< 0
         xa(i+1)=xa(i);
         xb(i+1)=xr(i);
      end
      if f(xa(i))*f(xr(i))> 0
         xa(1)=xr(i);
         xb(1)=xb(i);
	  end      
      xr(i+1)=xa(i+1)-f(xa(i+1))*(xb(i+1)-xa(i+1))/(f(xb(i+1))-f(xa(i+1)));
       ea(i+1)=abs((xr(i+1)-xr(i))/(xr(i+1)))*100;
      printf('%2d \t %11.7f \t %11.7f \t %11.7f \t %7.3f \n', i+1,xa(i+1),xr(i+1),xb(i+1),ea(i+1));
      i=i+1;
   end
else
   printf('No existe una raíz en ese intervalo');
end
endfunction