Grapher has the ability to create a fit curve, limit it to an X range of data, and get the equation. To do so:

- Click on the
*Line/Scatter Plot*in the**Object Manager**to select it. - Click
**Home | Add to Graph | Fit Curve**. - Click on the
*Linear Fit*in the**Object Manager**to select it. - In the
**Property Manager**, click on the**Plot**tab. - In the
*Fitted Plot*section, uncheck the box next to*Apply fit to entire plot*. - Update the
*Minimum plot value to fit*(or*Minimum date/time*if the values in the data file are formatted as date/time). - Update the
*Maximum plot value to fit*(or*Maximum date/time*if the values in the data file are formatted as date/time) with the x values for the range of data you would like to use.

For example, if you want to limit the equation to the red area in the graph below, type in 40900 for*Minimum plot value to fit*and 40945 for the*Maximum plot value to fit*.

After changing the fit curve *Fitted Plot* properties, your fit curve will be reduced to the area in red.

- To get the equation of the line:

- Click the
*Linear Fit*plot. - In the
**Property Manager**, click on the**Plot**tab. - In the
*Statistics*section, set the desired*Number format*and*Significant digits*of the numbers in the equation, then click the button next to one of the commands.- Clicking on the
*Copy*button in the*Copy to clipboard*field copies the information to the Windows clipboard for pasting into Grapher or another program. - Clicking on the
*Display*button in the*Display report* - Clicking on the
*Insert*button in the*Insert into plot document*field allows you to click in the plot document window and have the fit curve information displayed as an editable text object.

- Clicking on the

- Click the

*Updated February 25, 2020*

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