Reflecting What determines where a rational function has a hole? A vertical asymptote? N When does a rational function have the horizontal asymptote y = 0? When does a rational function have another horizontal line as a horizontal asymptote? GOAL Some rational functions have asymptotes, others have holes, and some have both. Explain how you can identify, without graphing, which graphical Develo features a rational function will have. LEAR In Summary Tulia is demons Key Idea . The restricted values of rational functions correspond to two different kinds of graphical features: holes and vertical asymptotes. Need to Know . Holes occur at restricted values that result from a factor of the denominator that is also a factor of t