Chapter 4: Problem 11
In Exercises 11-24, state the amplitude and period of each sinusoidal function. $$ y=\frac{3}{2} \cos (3 x) $$
Short Answer
Expert verified
The amplitude is \( \frac{3}{2} \) and the period is \( \frac{2\pi}{3} \).
Step by step solution
01
Identify the Sinusoidal Function Parameters
The given function is of the form \( y = a \cdot \cos(bx) \), where \( a \) represents the amplitude and \( b \) affects the period. In this exercise, \( a = \frac{3}{2} \) and \( b = 3 \).
02
Determine the Amplitude
The amplitude of a sinusoidal function \( y = a \cdot \cos(bx) \) is the absolute value of the coefficient \( a \). Thus, the amplitude is \( |\frac{3}{2}| = \frac{3}{2} \).
03
Calculate the Period
The period of a cosine function \( y = a \cdot \cos(bx) \) is given by \( \frac{2\pi}{b} \). For this function, with \( b = 3 \), the period is \( \frac{2\pi}{3} \).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Trigonometric Functions
Trigonometric functions are a fundamental part of mathematics that study the relationships between angles and lengths in triangles.
There are three primary trigonometric functions: sine, cosine, and tangent.
There are three primary trigonometric functions: sine, cosine, and tangent.
- Sine (sin) relates the opposite side over the hypotenuse in a right triangle.
- Cosine (cos) relates the adjacent side over the hypotenuse.
- Tangent (tan) relates the opposite side over the adjacent side.
Cosine Function
The cosine function is one of the primary trigonometric functions and it is often represented as \( y = rac{3}{2} \cos(3x) \). In this function, the cosine wave starts at its maximum value and oscillates between the amplitude values.
The general equation of a cosine function is given by: \( y = a \cos(bx + c) + d \), where
The general equation of a cosine function is given by: \( y = a \cos(bx + c) + d \), where
- \(a\) represents the amplitude
- \(b\) controls the period
- \(c\) affects the phase shift
- \(d\) represents the vertical shift
Sinusoidal Function Parameters
Sinusoidal functions can be identified by their parameters in the equation \( y = a \cos(bx + c) + d \). Each parameter plays a critical role in the shape and position of the wave:
- Amplitude (\(a\)): Determines the height of the peaks and depths of the troughs from the central line.
- Frequency (\(b\)): Inversely affects the period of the wave. Higher values of \(b\) make the wave cycle more frequently.
- Phase Shift (\(c\)): Moves the wave left or right along the x-axis.
- Vertical Shift (\(d\)): Moves the wave up or down along the y-axis.
Amplitude
The amplitude of a sinusoidal function, notably a cosine function, refers to the maximum distance from its central axis or mean position. For \( y = \frac{3}{2} \cos(3x) \),
- The amplitude is determined by the coefficient in front of the cosine, in this case, \(\frac{3}{2}\).
- The amplitude represents the spread or intensity of the wave.
- It is calculated as the absolute value, \(|a|\), ensuring it is always a positive quantity.
Period Calculation
The period of a sinusoidal function indicates how long it takes to complete one full cycle of the wave. For a cosine function \( y = a \cos(bx) \), the period is calculated using the formula \[ \text{Period} = \frac{2\pi}{|b|} \].
For the given function \( y = \frac{3}{2} \cos(3x) \),
For the given function \( y = \frac{3}{2} \cos(3x) \),
- Set \(b = 3\),
- the period would be \(\frac{2\pi}{3}\).