Chapter 4: Problem 3
Use the techniques of shifting, stretching, compressing, and reflecting to sketch at least one cycle of the graph of the given function. $$ y=2-\sin x $$
Short Answer
Expert verified
The graph is a vertically shifted and reflected sine wave with peaks at 3 and troughs at 1.
Step by step solution
01
Identify the Base Function
The given function is \( y = 2 - \sin x \). The base function here is \( \sin x \). Understanding how the base function behaves will help us apply transformations.
02
Recognize Transformations
In \( y = 2 - \sin x \), we identify two transformations: a vertical shift and a reflection. The base function \( \sin x \) is reflected across the x-axis, because of the negative sign before it, giving us \( -\sin x \). It is then shifted upwards by 2 units due to the +2.
03
Graph the Reflected Function
Start by graphing \( -\sin x \). The reflection across the x-axis means for any point \( (x, \sin x) \), we now have \( (x, -\sin x) \). Thus, the maximum amplitude becomes -1, and the minimum becomes 1.
04
Apply the Vertical Shift
Now, take the reflected function \( -\sin x \) and shift the entire graph upward by 2 units. This means the highest value of the sine wave is 2 + 1 = 3, and the lowest value is 2 - 1 = 1.
05
Sketch at Least One Cycle
The sine function \( \sin x \) has a period of \( 2\pi \). Therefore, one full cycle of \( -\sin x \), spanning from 0 to \( 2\pi \), will fit the transformations. Mark the key points: starting at \( (0, 2) \), peak at \( (\frac{\pi}{2}, 3) \), crosses the middle line at \( (\pi, 2) \), minimum at \( (\frac{3\pi}{2}, 1) \), and back to starting level at \( (2\pi, 2) \).
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.
Vertical Shift
When working with transformations of graphs, a vertical shift is a straightforward adjustment. It involves moving a graph up or down without altering its shape. For the function \( y = 2 - \sin x \), the "+2" in the equation signifies a vertical shift. Specifically, each point on the graph \( -\sin x \) is moved 2 units upwards.
This means, for every point \((x, -\sin x)\), it shifts to \((x, -\sin x + 2)\).
This affects the range of the function:
This means, for every point \((x, -\sin x)\), it shifts to \((x, -\sin x + 2)\).
This affects the range of the function:
- The highest value increases by 2 units.
- The lowest value increases by 2 units.
Reflection
Reflections are another central aspect of graph transformations. For the function \( y = 2 - \sin x \), the reflection occurs due to the negative sign in front of \( \sin x \).
This reflects the graph over the x-axis. In simpler terms, the peaks and troughs of the wave are inverted. For any point \((x, \sin x)\), it becomes \((x, -\sin x)\).
This reflects the graph over the x-axis. In simpler terms, the peaks and troughs of the wave are inverted. For any point \((x, \sin x)\), it becomes \((x, -\sin x)\).
- The original peaks of \( \sin(x) \) at 1 become troughs at -1 for \( -\sin(x) \).
- Conversely, the original troughs of \( \sin(x) \) at -1 are peaks at 1 for \( -\sin(x) \).
Trigonometric Functions
Trigonometric functions, like sine and cosine, are foundational in mathematics, especially in understanding waves and oscillations. The base function in the exercise is \( \sin(x) \), a periodic function that oscillates between -1 and 1. This periodic nature (period \( 2\pi \)) means it repeats its pattern every \( 2\pi \) units.
- Key characteristics include amplitude, period, and frequency.
- \( \sin(x) \) has peaks at \( 1 \), troughs at \( -1 \), and crosses the x-axis periodically.
Sinusoidal Graphs
Sinusoidal graphs are a type of periodic graph that visually represent sine and cosine functions. These graphs are characterized by their wave-like shape, with consistent amplitude and wavelength.
In the problem, we begin with \( y = \sin x \), a classic sine wave.
In the problem, we begin with \( y = \sin x \), a classic sine wave.
- The function \( y=2-\sin x \) transforms this wave into a reflected and shifted version.
- Such modifications result in different maximum and minimum points, but the wave nature remains.