{$N+}Program M;

CONST
	st=2;
        h=0.01;
TYPE
	vektor2=array[1..st] of real;
	vektor3=array[1..st] of integer;
	matice=array[1..st,1..st] of real;

FUNCTION f1(x,y:real):real;
BEGIN
    f1:=x*x+4*x-y*y-2*y-1;
END;

FUNCTION df1dx(x,y:real):real;
BEGIN
    df1dx:=1/(2*h)*(f1(x+h,y)-f1(x-h,y));
END;

FUNCTION df1dy(x,y:real):real;
BEGIN
    df1dy:=1/(2*h)*(f1(x,y+h)-f1(x,y-h));
END;

FUNCTION f2(x,y:real):real;
BEGIN
    f2:=x*x+5*y-4;
END;

FUNCTION df2dx(x,y:real):real;
BEGIN
    df2dx:=1/(2*h)*(f2(x+h,y)-f2(x-h,y));
END;

FUNCTION df2dy(x,y:real):real;
BEGIN
    df2dy:=1/(2*h)*(f2(x,y+h)-f2(x,y-h));
END;

{$I GAUSSJ.PAS}

VAR
   n,i:integer;
   xo,yo,xn,yn:real;
   a:matice;
   b:vektor2;

BEGIN

n:=1;
xo:=1;
yo:=1;

FOR i:=1 to 20 DO BEGIN
WRITELN('Krok ',n,' (xo,yo) (',xo:6:5,',',yo:6:5,') (f1,f2) (',f1(xo,yo):6:5,',',f2(xo,yo):6:5,')');

a[1,1]:=df1dx(xo,yo);
a[1,2]:=df1dy(xo,yo);
a[2,1]:=df2dx(xo,yo);
a[2,2]:=df2dy(xo,yo);

b[1]:=-f1(xo,yo);
b[2]:=-f2(xo,yo);

GAUSSJ(a,b);

xo:=xo+b[1];
yo:=yo+b[2];

n:=n+1;
READLN;

END;

READLN;

END.