program Pascal_162753;

type
	TIFunc=function (x:double):double;
{ Интегрируемая функция }
function f(x:double):double;
begin
	f:=1.0/sqrt(2*x*x+3);
end;
{ Метод прямоугольников }
function IRect(IFunc:TIFunc;A,B:double;Intervals:word):double;
var
	sum,step:double;
begin
	sum:=0;
	step:=(B-A)/Intervals;
	A:=A+step/2;
	while A<B do begin
		sum:=sum+step*IFunc(A);
		A:=A+step;
	end;
	IRect:=sum;
end;
{ Метод симпсона }
function ISympson(IFunc:TIFunc;A,B:double;Intervals:word):double;
var
	sum,step:double;
	i:LongInt;
function x(i:LongInt):double;
begin
	x:=A+step*i;
end;
begin
	step:=(B-A)/2/Intervals;
	sum:=IFunc(x(1))*4;
	for i := 1 to Intervals-1 do
		sum:=sum+IFunc(x(i*2+1))*4+IFunc(x(i*2))*2;
	ISympson:=(IFunc(x(0))+IFunc(x(2*Intervals))+sum)*step/3;
end;

var
	A,B:double;
	Intervals:word;
begin
	Write('A=');ReadLn(A);
	Write('B=');ReadLn(B);
	Write('Intervals=');ReadLn(Intervals);
	WriteLn('Rectangles=',IRect(@f,A,B,Intervals):0:5);
	WriteLn('Sympson=',ISympson(@f,A,B,Intervals):0:5);
	ReadLn;
end.

A=0.8
B=2.4
Intervals=10
Rectangles=0.57373
Sympson=0.57383