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.
A similarity (also called a similarity transformation or similitude) of a Euclidean space is a bijection f from the space onto itself that multiplies all distances by the same positive real number r, so that for any two points x and y we have.