(4, 0)T

Vectors Aligned with X-Y Axes

A 2D vector that is aligned with a coordinate axis, as with (4,0)^T, has an orientation that is easy to see. It is 0 degrees, 90 degrees, 180 degrees, or 270 degrees.

The orientation of a vector is usually expressed as an angle with the positive x axis of a coordinate frame. There are two ways of doing this:

• The angle is 0^o to 360^o measured as a counter-clockwise rotation from the positive x axis.
• The angle is 0^o to +180^o measured as a counter-clockwise rotation from the positive x axis, or is 0^o to -180^o measured as a clockwise rotation from the positive x axis,