MPD.pas

program project1;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, crt
  { you can add units after this };

var E,a,b,c,Fa,Fb,Fc,x: Real;

function f(x: Real):Real;
begin
  f:=(sin(x)/cos(x))-((((sin(x)/cos(x))*(sin(x)/cos(x))*(sin(x)/cos(x)))+1)/3)+(0.2*((sin(x)/cos(x))*(sin(x)/cos(x))*(sin(x)/cos(x))*(sin(x)/cos(x))*(sin(x)/cos(x))));
end;
 Begin
   Writeln('Enter limit a, b and accuracy E');
   Readln(a,b,E);
   Fa:=f(a);
   Fb:=f(b);
   Fc:=f(c);
   Repeat
     Begin
     If (Abs(Fa)<E)
     then writeln('x=',a)
     else
     If (Abs(Fb)<E)
     then writeln('x=',b)
     End;
     Begin
       c:=(a+b)/2;
     End;
     Begin
       If (Fa*Fc<0)
       then c:=b
       else
       If (Fc*Fb<0)
       then c:=a
     End;
   until (b-a<E);
   Begin
   Writeln('x=',c:5:3);
   End;
   Readkey;
 End.