File Exchange > Graphing >    Tangent

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Draw a tangent line at selected point of a data plot.

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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.


  1. Click the icon to open dialog. Change dialog settings as desired and press OK. A vertical line will be added to the graph.
  2. Drag the vertical line to select a desired point on the curve. The tangent line will update as you move the vertical line.
  3. 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.
  4. 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.


11/17/2015 v1.1 Supports duplicate values in x data.
8/16/2018 v1.2 Fixed bug for wrong data with multiple plots, support for Chinese version.
3/19/2019 v1.3 Support apparent tangent and xy exchanged graph
20/6/2019 v1.4 Change minimum version to Origin 2016

Reviews and Comments:

12/02/2019snowli@nguyendun, could you email details of which part isn't clear to
Thanks, Snow

12/01/2019nguyendunPoor description. Cannot understand or apply



07/23/2019hxczsbVery gooood!

05/17/2019OriginLabHi ncepu2011ncepu,

Yes, this upgraded app requires Origin 2019b as a minimum version. It doesn't support running in Origin 2018. You can download our 2019b trail to try this app,

05/16/2019ncepu2011ncepuCan only the latest version of origin use this APP? What about the 2018 version? Where can I download APP without updates?

04/25/2019OriginLabHi anaalv, this app has been updated and the minimum version of Origin needs 2019b, which is the latest version, newer than 2019

04/24/2019anaalvI cannot get it to download even though I am currently running Origin2019. Help please.