Examples of limits, for which solutions are obvious. lim_{x → +∞} x = +∞. Similar: lim_{x → +∞} 2x = +∞, lim_{x → +∞} 5x^2 = +∞, lim_{x → +∞} 7x^3 = +∞. lim_{x → +∞} (-x) = -∞. Similar: lim_{x → +∞} (-2x) = -∞, lim_{x → +∞} (-5x^2) = -∞, lim_{x → +∞} (-7x^3) = -∞. lim_{x → +∞} 1/x = 0. Similar: lim_{x → +∞} 1/2x = 0, lim_{x → +∞} -5/x^2 = 0, lim_{x → +∞} 7/x^3 = 0, lim_{x → +∞} -9/x^4 = 0.