There are several causes of dry mouth: 1  Effects of certain medications. 2  Side effects of certain medical conditions, for example SjÃ¶gren's syndrome, and infections. 3  Side effect of certain medical treatments.  Nerve 1  damage. Dehydration.  Surgical removal of the salivary 1  glands. Lifestyle.
Euclidean geometry. Euclidean geometry is a mathematical system attributed to the Alexandrian Greek mathematician Euclid, which he described in his textbook on geometry: the Elements. Euclid's method consists in assuming a small set of intuitively appealing axioms, and deducing many other propositions (theorems) from these.
In mathematics, the standard basis (also called natural basis or canonical basis) for a Euclidean space is the set of unit vectors pointing in the direction of the axes of a Cartesian coordinate system. For example, the standard basis for the Euclidean plane is formed by vectors. and the standard basis for three-dimensional space is formed by vectors. Here the vector e x points in the x direction, the vector e y points in the y direction, and the vector e z points in the z direction.