A sultan is an Islamic monarch. Sultan is usually used by monarchs of Arabic, Turkish or Malaysian ethnicity as opposed to Khan or Shah. In modern English, the term is gradually being replaced by king. The sultan's domain is properly called a sultanate. The feminine form is sultana.
... below for generalizations) with a being non-zero. These solutions are also called the roots of the equation. The formula reads
<math>
x=\frac{-b \pm \sqrt ...