# octant

The coordinate planes ($yz$-plane, $zx$-plane, $xy$-plane) the space $\mathbb{R}^{3}$ into eight trihedral angles, which are called the octants of the space.  The magnitude of each octant as a solid angle is $\frac{\pi}{2}$.

Any coordinate of a point moving in a certain octant preserves its sign (http://planetmath.org/SignumFunction).  One calls the octant, where all three coordinates are nonnegative, the first octant.  The other octants have no agreed numbering; see still http://de.wikipedia.org/wiki/Oktant_(Geometrie)Wikipedia.

Title octant Octant 2013-03-22 18:51:53 2013-03-22 18:51:53 pahio (2872) pahio (2872) 5 pahio (2872) Definition msc 51N20 Quadrant first octant