прикладная математика

program trynytrobutan;
uses crt;

function fun(x:real):real;
          begin
          fun:=3*x-ln(x)-5;
          end;

function koren(a,b:real): real;
          var c:real;
          begin
          while (b-a)>0.001 do
                begin
                c:=(a+b)/2;
                if fun(a)*fun(c) > 0 then a:=c else b:=c;
                end;
          koren:=(a+b)/2;
          end;

begin
clrscr;
writeln('Koren v to4ke X=',koren(2,3));   
readkey;
end.