program raiz_sec;

Var m,x :real;
    a,b :real;
    n	:integer;
    
function f(x : real) : real;
Begin
  f:= x*sin((x+6)/(x+13));
end;

Begin
  x := -6.5;
  a := -6.5; b:=-5.9;
  n :=0;
  while  (abs( f(x) ) > 0.00000001) do
  begin 
    m := (f(b)-f(a))/(b-a);
    x := a - f(a)/m;
    if (f(x)*(a) <= 0) then  a := x
    else b := x;
    writeln("x = ", x, "  f(x) = ", f(x));
    n := n + 1;
  end;
  writeln("Fiz ",n," tentativas x = ",x," f(x) = ",f(x));
end.