2.2 Function editor The funktioneditor is a window, in which alle present functions are listed and can be edited. A function from the list-gadget appears in the string-gadget at the top of the window by clicking the function. If finish the entered or modified string with pressing <return>, the functionterm gets automatically interpreted. If the interpreter detects an error in the function, the error gets displayed in the "error" gadget below, and the "bad" function will appear in italics in the function-list. Of course such a bad function cannot be plotted or analyzed! Pressing the HELP-key over the function or error gadget shows immediately the "Functions"-chapter of the documentation where you can find information about the function-syntax. In the string-gadget "Graph" with the popup-list all existing graphs are shown by their names. You can give an individual name to every graph. When you double-click a graph in the list it will appear in the foreground. For a selected function you can define, whether and in which color and pattern it should be visible in the selected graph. A double-click to a function toggles the visible-mark as if you had clicked onto the visible-gadget. A function that appears in the selected graph ist marked with a preceding ">" in the function-list. Changes been made on a visible function will then be executed when you click "Redraw" in the graph-window - not before! This allows you to do more than one change at once without a time-consuming redraw after every change. As long as the function-editor is active, the following menus can be selected: Project New Graph... - Creates a new graph-window. The graph type ( 2D-graph or SIRDS-graph) has to be specified in a little requester. Help... - Opens the context-sensitive online-help like pressing the HELP-key About... - Opens an info-window Quit - Quit Graph2D Functions Clear all - The functionlist will be deleted Load ... - Load a functionlist Append... - Append a functionlist (without deleting the actual one) Save as... - Save the functionliste Edit New - A new, "empty" function will be added to the list at the selected position and can be immediately edited Cut - The selected function will be cut out of the list Paste - A former cut-out function will be added to the list at the selected position Discussion Complete - Discussion Zero-points - Zero-points Extrema - Extrema Turning-points" - Turning-points Monotony - Monotony Symmetry - Symmetry Miscellanious Simplify - A simplified aequivalent of the selected function will be added to the list Derive - The derivation of the selected function will be added to the list num. integration... - Allows you to calculate the integral of the selected function in an intervall you have to specify via the "Simpson"-formula Value-table... - A value-table of the selected function in a definable intervall and with a selectable step- width will be generated Tangente ... - A new function will be added to the list which represents a tangete on a definable point of the selected function math. notation... - Opens the notation-window with the selected function