You can drag an FCurve manually to scale a group of keyframes negatively and view the result in the Viewer window. This is useful if you want to mirror or invert certain types of animation.

To negatively scale an FCurve:

1. Drag-select a group of keyframes on a FCurve. This illustration show keys on the x-translation curve.
   
2. Select the top white arrow.
   
3. Drag the top white arrow so that it is below the bottom white arrow. This inverts the direction travelled along the x-axis.
   
   NoteYou can also Ctrl-middle-drag to scale about a point, similar to the Autodesk Maya F-Curve editor.