Guess limits of a simple functions as x → +∞. lim_{x → -∞} x^3 = -∞; x: -1, -2, -3, -4 → -∞; x^3: -1, -8, -27, -64 → -∞. lim_{x → -∞} x^2 = +∞; x: -1, -2, -3, -4 → -∞; x^2: 1, 4, 9, 16 → -∞. lim_{x → -∞} 1/x = 0; x: -1, -2, -3, -4 → -∞; 1/x: -1/1, -1/2, -1/3, -1/4 → 0. lim_{x → -∞} 1/x^2 = 0; x: -1, -2, -3, -4 → -∞; 1/x^2: 5/1, 5/4, 5/9, 5/16 → 0.