Determine the value of without using a calculator or the unit circle.
Table of contents
- 0. Review of College Algebra4h 45m
- 1. Measuring Angles40m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
4. Graphing Trigonometric Functions
Graphs of the Sine and Cosine Functions
Problem 1
Textbook Question
Determine the amplitude of each function. Then graph the function and y = sin x in the same rectangular coordinate system for 0 ≤ x ≤ 2π. y = 4 sin x
Verified step by step guidance1
Identify the general form of the sine function, which is \(y = A \sin x\), where \(A\) represents the amplitude.
Recall that the amplitude of a sine function is the absolute value of the coefficient in front of \(\sin x\), so amplitude \(= |A|\).
In the given function \(y = 4 \sin x\), the coefficient \(A\) is 4, so the amplitude is \(|4|\).
To graph the function \(y = 4 \sin x\) along with \(y = \sin x\) on the same coordinate system for \(0 \leq x \leq 2\pi\), plot points for both functions at key values of \(x\) such as \$0$, \(\frac{\pi}{2}\), \(\pi\), \(\frac{3\pi}{2}\), and \(2\pi\).
Note that \(y = 4 \sin x\) will have peaks at \$4\( and troughs at \)-4\(, while \(y = \sin x\) has peaks at \)1\( and troughs at \)-1$, so the graph of \(y = 4 \sin x\) is a vertically stretched version of \(y = \sin x\) by a factor of 4.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Amplitude of a Sine Function
The amplitude of a sine function y = a sin x is the absolute value of the coefficient a. It represents the maximum vertical distance from the midline (usually the x-axis) to the peak of the wave. For y = 4 sin x, the amplitude is 4, meaning the graph oscillates between -4 and 4.
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Amplitude and Reflection of Sine and Cosine
Graphing Sine Functions
Graphing a sine function involves plotting points based on its amplitude, period, and phase shift. The basic sine curve y = sin x oscillates between -1 and 1 with a period of 2π. For y = 4 sin x, the shape is similar but scaled vertically by a factor of 4, stretching the wave.
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Graph of Sine and Cosine Function
Comparing Functions on the Same Coordinate System
Plotting y = 4 sin x and y = sin x together helps visualize differences in amplitude. Both share the same period and phase but differ in vertical stretch. This comparison highlights how amplitude affects the height of the sine wave without changing its frequency or phase.
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Determining Different Coordinates for the Same Point
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