Example

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

For the radical function f(x)=x+3f(x) = \sqrt{x + 3}, the index is an even number (22), so the radicand must be greater than or equal to zero (x+30x + 3 \ge 0). Solving this inequality yields x3x \ge -3, establishing the domain as all values x3x \ge -3, which is written in interval notation as [3,)[-3, \infty). To graph the function, select xx-values within this interval that will give a radicand that is a perfect square, making it easy to take the square root. Choosing xx-values of 3-3, 2-2, 11, and 66 yields radicands of 00, 11, 44, and 99, respectively, resulting in the ordered pairs (3,0)(-3, 0), (2,1)(-2, 1), (1,2)(1, 2), and (6,3)(6, 3). Plotting these points creates a continuous curve starting at (3,0)(-3, 0). By observing the resulting graph, it is evident that the yy-values of the function are greater than or equal to zero, which means the range is [0,)[0, \infty).

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Updated 2026-05-26

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