const xn=-2; xk=2; h=0.25;
var x,y,s:real; i,n,k:integer;
begin
x:=xn-h;
n:=round((xk-xn)/h)+1;
s:=0; k:=0;
writeln(' x     y');
for i:=1 to n do
 begin
 x:=x+h;
 y:=cos(2*x);
 if y<0 then begin s:=s+y; k:=k+1; end;
 writeln(x:4:2,y:7:3);
 end;
if k>0 then writeln('sred=',s/k);
end.

Пример работы программы:
 x     y
-2.00 -0.654
-1.75 -0.936
-1.50 -0.990
-1.25 -0.801
-1.00 -0.416
-0.75  0.071
-0.50  0.540
-0.25  0.878
0.00  1.000
0.25  0.878
0.50  0.540
0.75  0.071
1.00 -0.416
1.25 -0.801
1.50 -0.990
1.75 -0.936
2.00 -0.654
sred=-0.759476651369786