Learn how to use OriginPro8 for curve fitting

originpro8 is a graphic visualization and data analysis software developed by Origin Lab in the United States. The software focuses on data analysis and drawing. Data analysis mainly includes various complete mathematical analysis functions such as statistics, signal processing, image processing, peak analysis and curve fitting. It is very It is powerful, but many novice friends may not know how originpro8 fits curves, so if you don’t know, let’s take a look!

How to fit the curve with originpro8

1. Select the data and click on the icon pointed by the arrow in the figure to generate a scatter plot.
Note: You must select the data first before you can generate a graph!

2. Select the points in the scatter plot and click Analysis - Fitting - Nonlinear Curve Fit - Open Dialog on the toolbar to open the curve fitting dialog box.
Note: Be sure to select the points in the scatter plot first, and then click on the toolbar!

3. In the dialog box, select "User Defined" for the Category option, and then click the button pointed by the arrow to open the dialog box for creating a new equation.

In the dialog box: the Function Name column allows you to name the equation (English only), this time it is named "NewFunction123"; in the Function Type column, select the second "Equations", and then click next to proceed to the next step.

4. Enter the parameter settings. The first and second lines are the independent variable x and the dependent variable y. The third line is the equation parameters you need to set. Take the quadratic equation of one variable as an example. Set Parameters a, b, c (letters and punctuation marks must be in English input method), then click next to proceed to the next step.

5. Enter the equation input, as shown in the figure, enter the quadratic equation in the red line box. (Letters and symbols must be in English input method).
The basic settings have been completed here, just keep clicking next, and finally click finish!

6. Return to the initial curve fitting dialog box, and you will find that the created equation NewFunction123 has been created in the drop-down menu of the Function column.

7. Then click the "Parameters" tab and check Fixed to fix the parameters; then click the button in step 2 of the figure to perform fitting until the parameters remain unchanged and the desired value is reached. to achieve the best results; finally click Fit to generate the fitting results.

8. The final generated graph is as shown below. The correlation coefficient, goodness-of-fit determination coefficient R-square and the values ​​of each parameter will be displayed in the table.

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