when x is very large, the graph of y=(1/2)^x approaches the x-axis. that is, as x gets larger and larger (farther to the right along the curve), the closer the curve gets to the x-axis. in this situation, the x-axis is called an asymptote of y=(1/2)^x. does function y=(1/2)^x have a vertical asymptote? in other words, is there a vertical line that the graph above approaches? why or why not