Use the sum function to operate on two or more previously saved X–Y data objects (each object is a collection of ordered pairs) to produce a new X–Y data object. The sum function accepts two or more commutative arguments.
Note: This function has the same behavior as the + symbol. For more information, see “Using addition on X–Y data objects,” Section 29.4.5.
To sum two or more X–Y data objects:
Locate the Operate on XY Data dialog box.
From the main menu bar, select Tools
XY DataCreate. Click Operate on XY data in the dialog box that appears; then click Continue. The Operate on XY Data dialog box appears.
From the Operators listed, click sum(A,A,...).
The sum function appears in the expression window.
From the XY Data choices, click the names of two or more X–Y data objects to sum together and click Add to Expression. You can choose from all X–Y data objects previously saved within this session (listed alphabetically in the XY Data field).
The X–Y data object names appear, separated by commas, within the sum function parentheses in the expression window.
To continue to build your expression, position the cursor in the expression window and type in or select the functions, operators, and X–Y data you want to include.
To evaluate and display your expression, click Plot Expression.
To save your new X–Y data object, click Save As and then provide a name in the dialog box that appears.
Saving your data object makes it available for future operations within this session and for inclusion in X–Y plots containing multiple data objects.
When you are finished, click Cancel to close the dialog box.
