Построить график по заданной функции

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
#include "math.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
float x;
const e = 2.71828;
for(x = -20;x >= -20 && x <= 20; x=x+0.1){
Series1->AddXY(x, pow(x, 3)*1.0/3.0 - 2*pow(x, 2) + 4*x - pow(e, x),"", clBlue);
};
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
Series1->Clear();
}
//---------------------------------------------------------------------------