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Ch. 4 - Graphs of the Circular Functions
Chapter 5, Problem 4.2

Fill in the blank(s) to correctly complete each sentence.
The graph of y = cos (x - π/6) is obtained by shifting the graph of y = cos x ______ unit(s) to the ________ (right/left).

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1
Identify the transformation applied to the function y = \cos(x).
Recognize that y = \cos(x - \frac{\pi}{6}) represents a horizontal shift.
Understand that a function y = \cos(x - c) shifts the graph of y = \cos(x) to the right by c units if c is positive.
Determine the value of c in the expression x - \frac{\pi}{6}, which is \frac{\pi}{6}.
Conclude that the graph of y = \cos(x - \frac{\pi}{6}) is obtained by shifting the graph of y = \cos(x) \frac{\pi}{6} units to the right.

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Key Concepts

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

Phase Shift

Phase shift refers to the horizontal translation of a periodic function along the x-axis. In the context of cosine functions, a positive phase shift indicates a shift to the right, while a negative phase shift indicates a shift to the left. The expression inside the cosine function, such as (x - π/6), determines the direction and magnitude of this shift.
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Phase Shifts

Cosine Function

The cosine function is a fundamental trigonometric function defined as the ratio of the adjacent side to the hypotenuse in a right triangle. Its graph is a wave that oscillates between -1 and 1, with a period of 2π. Understanding the basic shape and properties of the cosine function is essential for analyzing transformations like shifts.
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Graph of Sine and Cosine Function

Transformations of Functions

Transformations of functions involve changes to the graph of a function, including shifts, stretches, and reflections. For trigonometric functions, horizontal shifts occur when a constant is added or subtracted from the variable inside the function. Recognizing how these transformations affect the graph is crucial for accurately completing the sentence regarding the cosine function.
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