program trap_rect;
uses wincrt;
const pi=3.1415259;
var i,n:longint;
a,b:real;

function f(x:real):real;
begin
f:=sin(x);
end;
function rect(a,b:real;n:integer):real;
var x,h,s:real;
begin
s:=0;
h:=(b-a)/n;
x:=(a+h)/2;
for i:= 1 to n do
begin
s:=s+f(x)*h;
x:=x+h;
end;
rect:=s;
end;
function trap(a,b:real;n:integer):real;
var x,h,s:real;
begin
s:=0;
h:=(b-a)/n;
x:=a;
for i:= 1 to n do
begin
s:=s+(f(x)+f(x+h))/2*h;
x:=x+h;
end;
trap:=s;
end;

procedure saisir;
begin
readln(a,b);
readln(n);
end;

begin
saisir;
writeln('Methode des rectangles : ',rect(a,b,n));
writeln('Methode des trapèzes :   ',trap(a,b,n));

end.