Rectangular unit vectors | Improve Society

The rectangular unit vectors $\bold{i}$ , $\bold{j}$ and $\bold{k}$ are unit vectors having the direction of the positive x, y, and z axes of a rectangular coordinate system. We use right-handed rectangular coordinate system unless otherwise specified. Such systems derive their name from the fact that a right threaded screw rotated through 90° from Ox to Oy will advance in the positive z direction. In general, three vectors $\bold{A}$ , $\bold{B}$ and $\bold{C}$ which have coincident initial points and are not coplanar are said to form a right-handed system if a right threaded screw rotated through an angle less than 180° from $\bold{A}$ to $\bold{B}$ will advance in the direction $\bold{C}$ .