Functions and Function Notation Flashcards

Grade 8 · Math · Flashcards

Essential vocabulary and rules for understanding functions and function notation.

Flashcards

Function: A relation in which every input (x) is paired with exactly one output (y)
Not a function: When one x-value maps to two or more different y-values
Domain: The set of all allowable input values (x-values)
Range: The set of all output values (y-values) a function can produce
f(x): Function notation; read 'f of x'; represents the output for a given input x
Evaluating f(a): Substitute a for every x in the function rule and simplify
Vertical line test: Graph is a function if NO vertical line intersects it more than once
Mapping diagram: Shows inputs on the left and outputs on the right with arrows; a function has exactly one arrow per input
Linear function: f(x) = mx + b; constant rate of change; graph is a straight line
Nonlinear function: Rate of change is not constant; graph is curved (e.g., f(x) = x²)
Input: The x-value fed into a function; also called the independent variable
Output: The y-value produced by a function; also called the dependent variable
Ordered pair: (x, y) pair showing input and corresponding output; e.g., if f(3)=7, write (3,7)