1. Open a new worksheet. 2. Right-click on the first column (A(X)) and select Set Column Values from the menu list. In the Set Column Values dialog box, enter sin(i). Click OK. Rows 1-30 will be filled in with values. Your t values most likely will not be row numbers (i); however, you could fill another column with the t values and then use sin(col(Tval)) assuming your column name was Tval.
Once you've generated the data you can highlight the Y column and click the scatter plot type button.
I'm not sure if I completely answered your question. Let me know.
We have not implemented this as of 6.1. We usually decide about new features, and plotting x(t), y(t) is certainly a very good one, by asking our users. So far, we have not heard from too many users about parametric function plotting.