Vẽ đồ thị hàm số sau: \(f\left( x \right) = \left\{ \begin{array}{l} - x + 1\,\,\,\,\,\,khi\,\,\,x < - 1\\1\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,khi\,\,\, - 1 \le x < 1\\{x^2}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,khi\,\,x \ge 1.\end{array} \right.\)