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Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 3, Problem 72

Begin by graphing the square root function, f(x) = √x. Then use transformations of this graph to graph the given function. h(x)=-√(x + 1)

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Start by identifying the base function, f(x) = √x. This is the square root function, which has a domain of x ≥ 0 and a range of y ≥ 0. Its graph starts at the origin (0, 0) and curves upward to the right.
Next, analyze the given function, h(x) = -√(x + 1). Notice that the transformation involves two changes: (1) the addition of 1 inside the square root, and (2) the negative sign outside the square root.
The transformation x + 1 inside the square root shifts the graph of f(x) = √x to the left by 1 unit. This is because adding a constant inside the function affects the x-values inversely.
The negative sign outside the square root reflects the graph across the x-axis. This means that all y-values of the graph are multiplied by -1, flipping the graph downward.
Combine these transformations: Start with the graph of f(x) = √x, shift it left by 1 unit, and then reflect it across the x-axis. The resulting graph represents h(x) = -√(x + 1).

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Key Concepts

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

Square Root Function

The square root function, f(x) = √x, is defined for x ≥ 0 and produces non-negative outputs. Its graph is a curve that starts at the origin (0,0) and increases gradually, reflecting the relationship between x and its square root. Understanding this function is crucial as it serves as the base for applying transformations.
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Imaginary Roots with the Square Root Property

Graph Transformations

Graph transformations involve shifting, reflecting, stretching, or compressing the graph of a function. In this case, the function h(x) = -√(x + 1) involves a horizontal shift to the left by 1 unit and a reflection across the x-axis. Mastery of these transformations allows for the accurate manipulation of the base graph to create new functions.
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Intro to Transformations

Reflection Across the X-Axis

Reflection across the x-axis occurs when the output values of a function are negated. For the function h(x) = -√(x + 1), this means that all y-values of the square root function are inverted, resulting in a graph that opens downward. This concept is essential for understanding how the shape and position of the graph change with transformations.
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Reflections of Functions