EXAMPLE 1 Graphing a Variation of y = sec x Graph y = 3 sec 2x. Solution: We first graph the reciprocal function y = 3 cos 2x (shown in gray) using the y = 3sec2x techniques from Section 5.5. The amplitude is 131 = 3. The period is 2 n 2 = 1. There is no phase shift or vertical shift. The graph of y = 3 sec 2x (shown in blue) has vertical asymptotes at the odd multiples of - where the graph of y = 3 cos 2x has x-intercepts