Текст программы USES crt;
var
n : integer;
s: real;
function f(x:real):real;
begin
f:=1-0.25*sin(x)*sin(x);
end;
procedure rect (a,b:real; n:integer; var s:real);
var
i : integer;
h,x: real;
begin
h:=(b-a)/n;
x:=a+h/2;
s:=0.0;
for i:=1 to n do
begin
s:=s+f(x);
x:=x+h;
end;
s:=s*h;
end;
BEGIN
clrscr;
rect (0,pi/2,40, s);
write('Интеграл = ',s:4:4);
readln;
END.