This app draws a tangent line at selected point of a data plot in a graph. A smoothing option is available for computing the derivative for noisy data.
Download the file Tangent.opx, and drag and drop it onto the Origin workspace. An icon will appear in the Apps Gallery window.
- Click the icon to open dialog. Change dialog settings as desired and press OK. A vertical line will be added to the graph.
- Drag the vertical line to select a desired point on the curve. The tangent line will update as you move the vertical line.
- Press the triangle button at the top right of the graph to display a context menu. Select "New Output" to add tangent line at currently selected point.
You can then move the cursor to other points on the curve to add additional tangent lines.
- Select "Preferences..." from the context menu to re-open the dialog to change settings.
When dialog is open, press "?" button, or F1 to open the help file.
It is best to use this app in Origin 2019B, or higher version. For lower version than Origin 2019B, if the plot is xy-exchanged, the horizontal for selecting data point is not able to be moved vertically by draging the line itself. The way to make this line moved is to drag one of the two handles, and even dragging the handle, the line would not move with the handle together, but it would jump to the position of the handle after the dragging done.