# rational function # vertical asymptote if f(a) doesn't exist and limit f(a) is pm infty # horizontal asymptote of b if lim_infty f(x) = c # slant asymptote or oblique asymptote # horizontal asymptotes of exp and logistic functions # "roots of numerator are x-intercepts" and "roots of denominator are vertical asymptotes" # task: sketch tougher functions