Extrema on an Open Interval

You can use the two sliders in this applet to move the endpoints, and . Notice the open circle at each endpoint, indicating that we're working on the open interval . Try to move the endpoints to create the following:
  • An open interval with a minimum and a maximum.
  • An open interval with only a minimum.
  • An open interval with only a maximum.
  • An open interval with neither a minimum nor a maximum.