The right-hand rule of xyz sequence in spatial rectangular coordinate system is: in spatial rectangular coordinate system, thumb direction is selected as X axis, index finger direction is selected as Y axis, and middle finger direction is selected as Z axis. The determined spatial rectangular coordinate system is called the right-handed coordinate system.

Spatial rectangular coordinate system:

The fixed point o across space is made into three mutually perpendicular number axes, all of which take o as the origin and have the same unit length. These three axes are called X axis (horizontal axis) respectively. Y axis (vertical axis). Z axis (vertical axis), collectively referred to as coordinate axis.

The order between the axes should conform to the right-handed rule, that is, the right hand holds the Z axis, so that the four fingers of the right hand turn from the positive direction of the X axis to the positive direction of the Y axis, forming a 90-degree right angle. At this time, the direction pointed by the thumb is the positive direction of the Z axis.

Such a coordinate system consisting of three coordinate axes is called right-handed rectangular coordinate system. Corresponding to this is the left-handed rectangular coordinate system. The right-handed rectangular coordinate system is commonly used in general mathematics, but it is different in other disciplines because of its convenient application.