You can use the dialog below to insert or edit a tangent or normal to a function.
To insert a new tangent or normal, you use *function list* and use → .

A tangent is a straight line that touches the graph of the function at a given point without crossing it. The tangent may however cross the graph elsewhere. A normal is a straight line perpendicular to the graph of the function at a given point. If the item is a standard function the point is identified by the x-coordinate, while the point is identified from the independent t-parameter for parametric and polar functions.

- Argument range
You can choose an interval for the tangent/normal.

*From*and*To*indicates the start and end of the interval. You can leave one or both of them blank to draw the graph from minus infinity to plus infinity.- Endpoints
Here you can choose to show markers at the start and/or end of the interval. If no interval is specified, the markers will be shown at the edge of the graphing area. The default is not to show any markers.

- Legend text
Enter a description to show in the

*legend*. If empty the function equation will be used.- Graph properties
You can choose between different line styles for which you want the tangent/normal to be drawn. You can choose between solid, dashed, dotted or a combination of these. You can also choose the width of the tangent/normal. The width is notified in screen pixels. There are also a lot of different colors you can choose between.