Cчитать двойной интеграл

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
 
 
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
int i,n,j,m;
float a,b,h,c,d,k,s,s1,x,y;
a=StrToFloat(Edit1->Text);
b=StrToFloat(Edit2->Text);
h=StrToFloat(Edit3->Text);
c=StrToFloat(Edit4->Text);
d=StrToFloat(Edit5->Text);
k=StrToFloat(Edit6->Text);
n=(b-a)/h;
m=(d-c)/k;
s=0;
for(i=0;i<n;i++)
{
s1=0;
x=a+i*h;
for(j=0;j<m;j++)
{
y=c+j*k;
s1=s1+(1/(x*y));
}
s=s+s1;
}
s=s*h*k;
Label7 -> Caption="Îòâåò: Èíòåãðàë ðàâåí : " +FloatToStr(s);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
Form1->Close();
}
//---------------------------------------------------------------------------