Table of contents
- 0. Review of College Algebra4h 43m
- 1. Measuring Angles39m
- 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 Tangent and Cotangent Functions
Problem 4.43a
Textbook Question
A rotating beacon is located at point A, 4 m from a wall. The distance a is given by
a = 4 |sec 2πt|,
where t is time in seconds since the beacon started rotating. Find the value of a for each time t. Round to the nearest tenth if applicable.
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t = 1.24
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1
Identify the given function for the distance: \( a = 4 |\sec(2\pi t)| \).
Substitute the given time \( t = 1.24 \) into the function: \( a = 4 |\sec(2\pi \times 1.24)| \).
Calculate the angle in radians: \( 2\pi \times 1.24 \).
Determine the secant of the calculated angle: \( \sec(\text{angle}) = \frac{1}{\cos(\text{angle})} \).
Multiply the absolute value of the secant by 4 to find \( a \).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Secant Function
The secant function, denoted as sec(x), is the reciprocal of the cosine function. It is defined as sec(x) = 1/cos(x). In the context of the given equation, sec(2πt) describes how the distance 'a' changes with time 't' as the beacon rotates, highlighting the relationship between circular motion and trigonometric functions.
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Trigonometric Functions and Time
Trigonometric functions, such as sine, cosine, and secant, are periodic and depend on the angle, which can be expressed in terms of time when dealing with rotating objects. In this case, the angle is represented as 2πt, indicating that the beacon completes one full rotation every second, thus affecting the distance 'a' over time.
Recommended video:
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Rounding and Precision
Rounding is the process of adjusting a number to a specified degree of accuracy, often to make it easier to work with or to present. In this problem, the instruction to round the value of 'a' to the nearest tenth emphasizes the importance of precision in mathematical calculations, particularly when interpreting results in real-world contexts.
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