Missing Trend Line and Forecast options in Analytics

In the Line Graph depicted by Alicia_Anderson , three values are being displayed (3 lines). The Trend line will only be available if you have a single line depicted in the graph. Otherwise, the Trend algorithm does not know which of the three to use in showing trend or how you might want to combine the existing three lines to show trend (sum, average, ??). The visualization is currently limited to showing trend for a single line.