The following flash shows how to add x-t and vx-t trace after the [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1031.0]simple harmonic motion simulation[/url] was created.
[flash=923,620]http://www.phy.ntnu.edu.tw/ntnujava/swf/shmxplotxtvxt.swf[/flash]