Dell Inspiron 17R Reference Manual page 130

Zoom
Allows you to increase or decrease the magnification of the screen content.
The zoom feature includes:
One finger zoom — Allows you to zoom in or out.
To zoom in: Move a finger up in the zoom zone (extreme left of the touchpad).
To zoom out: Move a finger down in the zoom zone (extreme left of the touchpad).
Pinch — Allows you to zoom in or zoom out by moving two fingers apart or bringing them closer together on the touchpad.
To zoom in: Move two fingers apart to enlarge the view of the active window.
To zoom out: Move two fingers close together to reduce the view of the active window.
Rotate
Allows you to rotate the active content on the screen. The rotate feature includes:
Twist — Allows you to rotate active content in 90° increments using two fingers where one finger is anchored and the other rotates.
Keeping the thumb in place, move the index finger in an arced direction right or left to rotate the selected item 90° clockwise or counterclockwise.
Flick