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Ch. 1 - Angles and the Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Not the one you use?Change textbook
Chapter 1, Problem 4a

Find a positive angle less than 2πœ‹ that is coterminal with 16πœ‹ 3

Verified step by step guidance
1
Understand that two angles are coterminal if they differ by an integer multiple of \(2\pi\). This means we can add or subtract \(2\pi\) any number of times to find coterminal angles.
Given the angle \(\frac{16\pi}{3}\), we want to find an angle \(\theta\) such that \(0 < \theta < 2\pi\) and \(\theta = \frac{16\pi}{3} - 2\pi k\) for some integer \(k\).
Express \(2\pi\) with a denominator of 3 to combine terms easily: \(2\pi = \frac{6\pi}{3}\). So, \(\theta = \frac{16\pi}{3} - k \times \frac{6\pi}{3} = \frac{16\pi - 6\pi k}{3}\).
Find the integer \(k\) such that \(\theta\) lies between 0 and \(2\pi\) (i.e., \(0 < \theta < \frac{6\pi}{3}\)). This involves solving inequalities for \(k\).
Once you find the appropriate \(k\), substitute back to get \(\theta = \frac{16\pi - 6\pi k}{3}\), which will be the positive coterminal angle less than \(2\pi\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Coterminal Angles

Coterminal angles are angles that share the same initial and terminal sides but differ by full rotations of 2Ο€ radians. To find a coterminal angle, you add or subtract multiples of 2Ο€ until the angle lies within the desired interval.
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Angle Measurement in Radians

Angles can be measured in radians, where 2Ο€ radians equal one full rotation (360 degrees). Understanding radian measure is essential for working with trigonometric functions and converting between angles.
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Modulo Operation with Angles

Finding an angle coterminal within a specific range involves using the modulo operation with 2Ο€. This process reduces any angle to an equivalent angle between 0 and 2Ο€ by subtracting multiples of 2Ο€.
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