program pasc;
var a0,a1:real;
n:integer;
const e=0.001;
begin
n:=1;
a1:=0.5;
repeat n:=n+1;
writeln(a1);
a0:=a1;
a1:=cos(a0)/2;
until abs (a1-a0)<e;
n:=n-1;
writeln('n=',n);
readln
end.
Вариант № 2
program asc;
var a,a1,f,s:real;
n:integer;
const e=0.001;
begin
n:=0;
F:=1;s:=-2;
repeat a:=s/f;
writeln(a:4:3);
s:=s*(-2);
n:=n+1;
f:=f*n
until abs(a)<e;
writeln('n=',n)
end.