Вычислить значение функции, заданной графически

program zad;
 
var
  x : Single;
  
begin
  Write('Input x='); ReadLn(x); Write('y=');
  if ((x >= -10) and (x <= 8)) then
    if (x <= -6) then
      WriteLn((sqrt(4 - sqr(x + 8)) - 2):4:2)
    else
      if (x <= 2) then
        WriteLn((x / 2 + 1):4:2)
      else
        if (x <=6 ) then
          WriteLn(0)
        else
          WriteLn((sqr(x - 6)):4:2)
  else
    WriteLn('Incorrect x!');
end.

program zad;
 
const c = 0.001;
 
var
  R, x, y, s1, s2, s3 : Real;
  Res : Boolean;
 
function Len(x1, y1, x2, y2 : Real) : Real;
begin
  Len := sqrt(sqr(x1-x2) + sqr(y1-y2));
end;
 
function Sq(a, b, c : Real) : Real;
var
  p : Real;
begin
  p := (a + b + c) / 2;
  Sq := sqrt(p * (p - a) * (p - b) * (p - c));
end;
 
 
begin
  Write('Input x, y='); ReadLn(x, y);
  Write('Input R='); ReadLn(R);
  Res := False;
  if ((Abs(x) <= R) or (Abs(y) <= R)) then
    if (x >= 0) then
    begin
      if (sqr(x) + sqr(y) <= sqr(R)) then
        Res := True;
    end
    else
    begin
      s1 := Sq(Len(0,0,0,R), Len(0,0,x,Abs(y)), Len(0,R,x,Abs(y)));
      s2 := Sq(Len(0,0,-R,R), Len(0,0,x,Abs(y)), Len(-R,R,x,Abs(y)));
      s3 := Sq(Len(-R,R,0,R), Len(-R,R,x,Abs(y)), Len(0,R,x,Abs(y)));
      if (s1 + s2 + s3 - Sq(R, R, (R * sqrt(2))) < c) then
        Res := True;
    end;    
  WriteLn(Res);
end.