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Key Parent Functions: Cubic and Absolute Value Functions

Study Guide - Smart Notes

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Cubic Function

Definition and Properties

The cubic function is a fundamental polynomial function in algebra, commonly written as:

  • General Form:

  • Domain: (all real numbers)

  • Range: (all real numbers)

The graph of the cubic function is an S-shaped curve that passes through the origin (0,0). It is symmetric with respect to the origin, making it an odd function (i.e., ).

Key Characteristics

  • Intercept: The function passes through the origin (0,0).

  • End Behavior: As , ; as , .

  • Increasing/Decreasing: The function is always increasing.

Example Table of Values

x

y = x^3

-2

-8

-1

-1

0

0

1

1

2

8

Example

  • For , .

  • For , .

Absolute Value Function

Definition and Properties

The absolute value function is another key parent function in algebra, defined as:

  • General Form:

  • Domain: (all real numbers)

  • Range: (all non-negative real numbers)

The graph of the absolute value function forms a "V" shape, with its vertex at the origin (0,0). The function is even, meaning .

Key Characteristics

  • Vertex: The lowest point is at (0,0).

  • Symmetry: The graph is symmetric about the y-axis.

  • Piecewise Definition:

    • For ,

    • For ,

Example Table of Values

x

y = |x|

-3

3

-2

2

-1

1

0

0

1

1

2

2

3

3

Example

  • For , .

  • For , .

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