program lenka_integral;

{$APPTYPE CONSOLE}

uses
  SysUtils;

const EPS = 0.001;
const A1 = 5.09;
const B1 = 5.1;
const A2 = 4.2;
const B2 = 4.27;
const A3 = 1.3;
const B3 = 1.38;
const P = 0.066666666667;

type Func = function(x : real) : real;
{$F+}
Function f1 (x : real): real;
begin
  f1 := 3 * (0.5 / (x + 1) + 1);
end;

Function f2 (x : real): real;
begin
  f2 := 2.5 * x - 9.5;
end;

Function f3 (x : real): real;
begin
  f3 := 5 / x;
end;

Function d1 (x : real): real;
begin
  d1 := -1.5 / ((x + 1) * (x + 1)) ;
end;

Function d2 (x : real): real;
begin
  d2 := 2.5;
end;

Function d3 (x : real): real;
begin
  d3 := - 5 / (x * x);
end;
{$F-}

Procedure root(f, g, f1, g1 : Func; a, b, EPS: real; var x : real);
var
d, c : real;
begin
if (f((a + b) / 2) - g((a + b) / 2) - (f(a) - g(a) + f(b) - g(b)) / 2) * f(a)  < 0 then
  begin
    d := b;
    c := d - (f(d) - g(d)) / (f1(d) - g1(d));
    while ((f(c) - g(c)) * (f(c - EPS) - g(c - EPS)) > 0)  do
    //while ((f(c) - g(c))) / ((f1(c) - g1(c))) > EPS do
      begin
      d := c;
      c := d - (f(d) - g(d)) / (f1(d) - g1(d));
      end;
  end
else
  begin
    d := a;
    c := d - (f(d) - g(d)) / (f1(d) - g1(d));
    while ((f(c) - g(c)) * (f(c + EPS) - g(c + EPS)) > 0)  do
    //while (f(c) - g(c)) / (f1(c) - g1(c)) > EPS do
      begin
      d := c;
      c := d - (f(d) - g(d)) / (f1(d) - g1(d));
      end;
  end;
x := c;
end;

Function simpson(f : Func; a, b : real; n : integer) : real;
var
i : integer;
s, h, x : real;
begin
s := 0;
h :=  (b - a) / n;
for i := 0 to n do
  begin
    x := a + h * i;
        if (i = 0) or (i = n) then
            s := s + f(x)
        else if (i mod 2 = 0) then
            s := s + f(x) * 2
        else
            s := s + f(x) * 4;
  end;
simpson := s * h / 3;
end;

Function abs(a : real) : real;
begin
abs := a;
if (a < 0) then
  abs := -a;
end;

Function integral(f : Func; a, b : real) : real;
var
n : integer;
i, i2 : real;
begin
n := 10;
i := simpson(f, a, b, n);
i2 := simpson(f, a, b, n * 2);
while (p * (abs(i - i2)) > EPS) do
  begin
  i := i2;
  i2 := simpson(f, a, b, n * 2);
  n := n * 2;
  end;
integral := i2;
end;

var
x1, x2, x3, y1, y2, y3, y4 : real;
begin
root(f1, f2, d1, d2, A1, B1, EPS, x1);
root(f2, f3, d2, d3, A2, B2, EPS, x2);
root(f1, f3, d1, d3, A3, B3, EPS, x3);

y1 := integral(f1, x3, x2);
y2 := integral(f3, x3, x2);
y3 := integral(f1, x2, x1);
y4 := integral(f2, x2, x1);
writeln(y1 - y2 + y3 - y4 : 9 : 9);
readln;
end.