# 6.13 Plot Functions with Parameters Defined in a Worksheet

## Summary

Origin can plot functions. It also can plot functions with parameters defined in a worksheet. The function graph can be updated automatically as the parameters in the worksheet change.

Minimum Origin Version Required: Origin 8.0 SR6

## What you will learn

This tutorial will show you how to:

• Define variables from a worksheet in the Set Values dialog box.
• Plot a function graph with parameters.
• Update a graph automatically when parameters are changed.

## Steps

Let us use this function as an example: y=p0+p1*x+p2*x^2

1. Set up a worksheet with three parameters p0, p1, p2 stored in Column A, Column B, Column C as shown below.
2. Click on the Add New Columns button on the Standard toolbar to add a new column to the worksheet.
3. Highlight Column D and then select Column: Set Column Values. Select Auto from the Recalculate drop-down. Type the script shown below to define the parameters in the Before Formula Scripts edit box. Click the OK button to close the dialog box.
Note that there is a green lock icon on the top right corner of Column D which indicates that the Recalculate Mode is Auto.
4. Click on the New Function button on the Standard toolbar(If there is not New Function button, select View: Toolbar to open the Customize dialog, and then go to Button Groups tab, select Standard group, and then drog the New Function button to Standard toolbar. ). The Plot Details dialog opens.
5. In the Plot Details dialog, set the options as follows and click the OK button to close the dialog box.
Click on the Rescale button on the Graph toolbar to adjust the graph's scales.
6. The function graph can be updated automatically when the parameters in the first row of the worksheet change. Change the value in the first row of Column 2 from 2 to 3. Click outside this cell to finish editing.
The function graph updates to reflect this change.

## Scripts

The script used in the Before Formula Scripts edit box of the Set Values dialog box is:

p0=col(1)[1];  //Specify Column A for p0.
p1=col(2)[1];  //Specify Column B for p1.
p2=col(3)[1];  //Specify Column C for p2.

The function in the F1(x) edit box of the Plot Details dialog box is as follows:

p0+p1*x+p2*x^2