Chapter 7: Problem 30
\(29-42\) . Find the amplitude, period, and phase shift of the function, and graph one complete period. $$ y=2 \sin \left(x-\frac{\pi}{3}\right) $$
Short Answer
Expert verified
Amplitude is 2, period is \(2\pi\), phase shift is \(\frac{\pi}{3}\) to the right.
Step by step solution
01
Understanding the Equation
The function we have is \( y = 2 \sin\left(x - \frac{\pi}{3}\right) \). This is a sine function of the form \( y = A \sin(Bx - C) \), where \( A \) is the amplitude, \( B \) affects the period, and \( C \) affects the phase shift.
02
Find the Amplitude
The amplitude \( A \) is the coefficient of the sine function. In \( y = 2 \sin\left(x - \frac{\pi}{3}\right) \), \( A = 2 \). Therefore, the amplitude is 2.
03
Find the Period
The period \( T \) of the sine function is given by the formula \( T = \frac{2\pi}{|B|} \), where \( B \) is the coefficient of \( x \) inside the sine function. Here, \( B = 1 \). So, the period \( T = \frac{2\pi}{1} = 2\pi \).
04
Find the Phase Shift
The phase shift is determined by \( \frac{C}{B} \) from \( y = A \sin(Bx - C) \). Here, \( C = \frac{\pi}{3} \) and \( B = 1 \). So, the phase shift \( \frac{\pi}{3} / 1 = \frac{\pi}{3} \). This means the graph shifts to the right by \( \frac{\pi}{3} \).
05
Sketching the Graph
To sketch one complete period, start right after the phase shift at \( x = \frac{\pi}{3} \) and go until \( x = \frac{\pi}{3} + 2\pi \). The sine curve will reach its maximum at \( y = 2 \) and its minimum at \( y = -2 \). The complete wave oscillates between those extremes over this interval.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Amplitude of the Sine Function
When studying a sine function, one of the key features we look out for is the amplitude. This lesson applies even when looking at the function \( y = 2 \sin\left(x - \frac{\pi}{3}\right) \). The amplitude is a measure of how much the wave oscillates above and below its average value, which is typically zero in the case of standard sine functions.
- Definition: In a sine function of the form \( y = A \sin(Bx - C) \), the amplitude is the absolute value of \( A \).
- For the example function, the coefficient \( A = 2 \). Hence, the amplitude is 2.
- This means the sine wave will reach a maximum height of 2 units and a minimum of -2 units from the horizontal axis.
- The wave extends equally above and below the centerline, making this characteristic easily identifiable in a graph.
Period of the Sine Function
The period of a sine function describes how long it takes for the wave to complete one full cycle. For the function \( y = 2 \sin(x - \frac{\pi}{3}) \), recognizing the period involves looking at the coefficient in front of the variable \( x \).
- Definition: The period \( T \) of a sine wave \( y = A \sin(Bx - C) \) is calculated using the formula \( T = \frac{2\pi}{|B|} \).
- In this case, \( B = 1 \). So, substituting into the formula gives \( T = \frac{2\pi}{1} = 2\pi \).
- This tells us the wave repeats every \( 2\pi \) units in the horizontal direction.
- A longer period would indicate a more stretched out wave, while a shorter period shows it is more compact.
Phase Shift of the Sine Function
Phase shift in a sine function reveals how much the graph is horizontally shifted from its standard position. This concept is crucial for drawing and interpreting the sine wave accurately for the function \( y = 2 \sin(x - \frac{\pi}{3}) \).
- Definition: The phase shift in \( y = A \sin(Bx - C) \) can be found using \( \frac{C}{B} \), where the term \( C \) determines the horizontal shift.
- In our equation, \( C = \frac{\pi}{3} \) and \( B = 1 \), resulting in a phase shift of \( \frac{\pi}{3} \).
- This means the entire sine graph moves \( \frac{\pi}{3} \) units to the right.
- The phase shift tells us where the sine wave's critical points move along the \( x \)-axis, like starting points and points of maximum and minimum values.