Вычисления указанной величины

#include <vcl.h>
#pragma hdrstop
#include <iostream>
#include <math.h>
 
#include "Unit1.h"
#define pi  3,1415927
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
double x, y, z, a, b , c, d, rez;
x = StrToFloat(Edit1->Text);
y = StrToFloat(Edit2->Text);
z = StrToFloat(Edit3->Text);
a = pow(2,pow(x,y));
b = pow(pow(3,x),y);
c = y*(atan(z)-pi/6);
d =   fabs(x)+ 1/(pow(y,2)+1);
rez = a+b-c/d;
Memo1->Lines->Add("При х = "+Edit1->Text
         + "; y = "+Edit2->Text+"; z = "+ Edit3->Text);
Memo1->Lines->Add("Результат rez = "+FloatToStrF(rez,ffFixed,7,4));
;
Label4->Visible = true;
 
}
//---------------------------------------------------------------------------
 
}