Find the Domain Of $x$ In the Expression $\sqrt { 81 - x ^ { 2 } }$

question 23

Multiple Choice

Find the domain of $x$ in the expression. Use a graphing utility to verify your result. $\sqrt { 81 - x ^ { 2 } }$

• A) \([ - 81,81 ]\)
• B) \(( - 9,9 )\)
• C) \([ - 9,81 )\)
• D) \([ - 9,9 ]\)
• E) \(( - 81,81 )\)

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Definitions:

Primary Key

A primary key is a unique identifier for each record in a database table, used to ensure that each entry is distinct and retrievable.

Principal Key

Another term for primary key, an attribute or set of attributes that uniquely identifies each record in a database table.

Foreign Key

An attribute in a database table that provides a link between data in two tables, typically to enforce referential integrity.

Main Key

A unique identification attribute or field in a database, functionally identical to a primary key.