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Ch. 2 - Graphs and Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 3, Problem 85

Graph each function. See Examples 6–8 and the Summary of Graphing Techniques box following Example 9. ƒ(x)=2√x+1

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Identify the base function and the transformations applied. The given function is \(f(x) = 2\sqrt{x} + 1\), which is a transformation of the basic square root function \(y = \sqrt{x}\).
Recall the graph of the parent function \(y = \sqrt{x}\), which starts at the origin \((0,0)\) and increases slowly to the right.
Apply the vertical stretch by a factor of 2. This means every \(y\)-value of \(\sqrt{x}\) is multiplied by 2, so the graph becomes steeper. The function now looks like \(y = 2\sqrt{x}\).
Apply the vertical shift upward by 1 unit. This means you add 1 to every \(y\)-value of \(2\sqrt{x}\), resulting in the function \(f(x) = 2\sqrt{x} + 1\).
Plot key points to sketch the graph: start with \(x=0\) giving \(f(0) = 2\sqrt{0} + 1 = 1\), then choose other \(x\) values (like 1, 4, 9) to find corresponding \(y\) values, and plot these points to see the shape of the graph.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Square Root Function

A square root function is of the form f(x) = √x, which produces outputs that are the non-negative square roots of x. Its graph starts at the origin (0,0) and increases slowly, only defined for x ≥ 0. Understanding this basic shape helps in graphing transformations.
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Function Transformations

Function transformations include shifts, stretches, and reflections applied to the parent function. For f(x) = 2√(x) + 1, the coefficient 2 vertically stretches the graph, and the +1 shifts it upward by 1 unit. Recognizing these changes helps in accurately sketching the graph.
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Domain and Range

The domain is the set of all input values for which the function is defined, and the range is the set of possible outputs. For f(x) = 2√x + 1, the domain is x ≥ 0 because of the square root, and the range is y ≥ 1 due to the vertical shift upward.
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