X̂ is the
Latin letter
The Latin script, also known as the Roman script, is a writing system based on the letters of the classical Latin alphabet, derived from a form of the Greek alphabet which was in use in the ancient Greek city of Cumae in Magna Graecia. The Gree ...
''X'' with a
circumflex
The circumflex () is a diacritic in the Latin and Greek scripts that is also used in the written forms of many languages and in various romanization and transcription schemes. It received its English name from "bent around"a translation of ...
. The letter is used in the modern
orthography
An orthography is a set of convention (norm), conventions for writing a language, including norms of spelling, punctuation, Word#Word boundaries, word boundaries, capitalization, hyphenation, and Emphasis (typography), emphasis.
Most national ...
of the
Aleut language
Aleut ( ) or is the language spoken by the Aleut living in the Aleutian Islands, Pribilof Islands, Commander Islands, and the Alaska Peninsula (in Aleut , the origin of the state name Alaska). Aleut is the sole language in the Aleut branch of ...
and in the current
Alaska Native Language Center
The Alaska Native Language Center, established in 1972 in Fairbanks, Alaska, is a research center focusing on the research and documentation of the Native languages of Alaska. It publishes grammars, dictionaries, folklore collections and research m ...
alphabet of the
Haida language
Haida (', ', ', ') is the language of the Haida people, spoken in the Haida Gwaii archipelago off the coast of western Canada and on Prince of Wales Island in Alaska. An endangered language, Haida currently has 24 native speakers, though revit ...
.
In both cases, it represents the sound .
In mathematics, x̂ often refers to the
unit vector
In mathematics, a unit vector in a normed vector space is a Vector (mathematics and physics), vector (often a vector (geometry), spatial vector) of Norm (mathematics), length 1. A unit vector is often denoted by a lowercase letter with a circumfle ...
in the +X direction. In statistics, it can also represent the predicted value for x, consistent with the
hat notation
A "hat" (circumflex (ˆ)), placed over a symbol is a mathematical notation with various uses.
Estimated value
In statistics, a circumflex (ˆ), called a "hat", is used to denote an estimator or an estimated value. For example, in the context of ...
.
References
Aleut language
Haida language
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