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Algebra and Functions
Functions
A function is a relation in which each element of the domain is paired with exactly one element of the range. On the SAT, unless otherwise specified, the domain of any function ƒ is assumed to be the set of all real numbers x for which ƒ(x) is a real number. For example, if ƒ(x) = 
the domain of ƒ is all real numbers greater than or equal to –2.
For this function, 14 is paired with 4, since
ƒ(14) = 
= 
= 4.
Note: the 
symbol represents the positive, or principal, square root. For example,
= 4, not ±4.
