Создание накопления суммы, и произведения, с функцией пользователя - Pascal ABC

Program nakoplenie;
var  sn:real;
 
procedure sumkop;
var k1,k2,k:integer; s:real;
begin
writeln;
k1:=1; k2:=18;
s:=0;
for k:=k1 to k2 do
 begin
 s:=s+ (
 function summa(k:integer):real;
 begin
 summa:=(abs(sin((sqr(k)/1.5)-2)))+11.73*cos(1.6*k-1)
 end;)
 writeln ('s=',s:3:5);
 end;
end;
 
procedure prkop;
var k1,k2,k:integer; p:real;
begin
writeln;
k1:=1; k2:=21;
p:=1;
for k:=k1 to k2 do
 begin
 p:=p*(function proiz(var k:integer):real;
 begin
 proiz:=(13,4*cos(abs(k))*sin(sqr(k)-2,25))
 end;)
 writeln ('p=',p:3:5);
 end;
end;

procedure funct;
var s,p:integer; z:real;
begin
x:=s;
y:=p;
z:=(5*x)-(2*y);
writeln ('z=',z:3:5);
end;

begin
 sumkop(s);
 
 prkop(p);
 
 funct(z);
end .