Polynomial (3rd Order) Curve with Equation

By Template Librarian|Published On: January 5, 2023 at 7:09 am PST|Last Updated: January 5, 2023 at 7:09 am PST|

Polynomial (3rd order) Curve with Equation

This tutorial will show how to use the TechGraph Editor to fit a third order polynomial curve to a set of XY data points. A third order polynomial equation that shows the a0, a1, a2 and a3 values is displayed as well. Shown below are the settings in the Data Table and the Edit Chart used to create this chart.

Data Table – Sample data can easily be changed or replaced by pasting data from an external worksheet.

Graph Type is Scatter.
X Data Type is Number. X Data column contains the X values.
Graph A series is set to Scatter and it contains the Y values.

Note: Click on the “Help” button on the toolbar to find out how to edit, delete, copy and paste in the Data Table.

Edit Chart – A set of icons (Titles, Settings, X Axis, Y Axis, Curves and Error Bars) to change the settings and appearance of the chart.

Settings – specify the color, marker type and size for Graph A marker.

Click on the “RedOrchid circle” (Graph Style) to show the marker Style for Graph A pop-up. You can change the Color, Type and Size for Graph A marker. Click on Apply to save the changes.
Click on “None” for Frame Style/Bkgrd. For this example, “None” is selected from the Frame Style list to suppress the chart frame.

X Axis

Enter values in Minimum, Maximum and Major Div to set the X Axis scale and divisions.
- Values for this example are Minimum = -3, Maximum = 3, Major Div = 6, and Minor Div = 5.
Checkbox for Draw Zero Axes is checked to center the X and Y Axes at zero location.

Y axis

Enter values in Minimum, Maximum and Major Div to set the Y Axis scale and divisions.
- Values for this example are Minimum = -30, Maximum = 30, Major Div = 6 and Minor Div = 5.

Curves & Error Bars

Click on “Polynomial” (Curve Fit) for Graph A to show the Curvefit Selection for Graph A pop-up. For this example, “Polynomial” is selected from the Selection list. “3” is selected from the Polynomial Order list for 3^rd order. Checkbox for Show Curve Fit Equation and Show Curve Fit Legend are checked. Click on Apply to save the changes.
Click on Curve Style for Graph A to show the Curve Style for Graph A pop-up. Curve Color (“black”) is selected for the polynomial curve color. Use the Thickness and Line Type selection list to change the line style. Click on Apply to save the changes.

Note: To move the location of the polynomial equation – click on the equation and it will be outlined with “bubbles”. Grab the center bubble and move to the desired location.

Edit Chart Toolbar Options

Print Chart prints your chart.
Download Image downloads your chart as an SVG(Scalable Vector Graphics) file or image file(PNG, JPEG, TIF, PDF).
Drawing Objects customize your chart with labels, lines, arrows, circles, images, and logos.

Polynomial (3rd Order) Curve with Equation