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Example

Determining the Domain, Graph, and Range of the Radical Function f(x)=x3f(x) = \sqrt[3]{x}

For the radical function f(x)=x3f(x) = \sqrt[3]{x}, the first step is to analyze the index to find the domain. Since the radical has an odd index (33), we know the radicand can be any real number. This tells us the domain encompasses all real numbers, written in interval notation as (,)(-\infty, \infty). To graph the function, we choose xx-values within this interval that will give a radicand that is easy to take the cube root of—specifically, perfect cubes. Selecting the xx-values 8-8, 1-1, 00, 11, and 88 yields the ordered pairs (8,2)(-8, -2), (1,1)(-1, -1), (0,0)(0, 0), (1,1)(1, 1), and (8,2)(8, 2). Plotting these coordinates creates an S-shaped curve that passes through the origin and extends infinitely in both directions. Looking at the graph, we see the yy-values of the function span all real numbers, meaning the range is also (,)(-\infty, \infty).

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Updated 2026-05-25

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