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Ch. 2 - Acute Angles and Right Triangles
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161Not the one you use?Change textbook
Chapter 3, Problem 1

Match each trigonometric function in Column I with its value in Column II. Choices may be used once, more than once, or not at all.

sin 30°

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1
Recall the definition of the sine function for an angle in degrees: \(\sin \theta\) represents the ratio of the length of the side opposite the angle \(\theta\) to the hypotenuse in a right triangle.
Identify the angle given in the problem, which is \(30^\circ\).
Use the known exact value of \(\sin 30^\circ\), which is a standard angle in trigonometry.
Recall or refer to the unit circle or special right triangles (like the 30°-60°-90° triangle) to find that \(\sin 30^\circ = \frac{1}{2}\).
Match \(\sin 30^\circ\) with the value \(\frac{1}{2}\) in Column II.

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Key Concepts

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

Basic Trigonometric Ratios

Trigonometric functions like sine, cosine, and tangent relate the angles of a right triangle to the ratios of its sides. Specifically, sine of an angle is the ratio of the length of the opposite side to the hypotenuse. Understanding these ratios is fundamental to evaluating functions such as sin 30°.
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Special Angles and Their Values

Certain angles, such as 30°, 45°, and 60°, have well-known exact trigonometric values. For example, sin 30° equals 1/2. Memorizing these special angle values helps quickly solve problems without a calculator and is essential for matching functions to their values.
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Function-Value Matching in Trigonometry

Matching trigonometric functions to their numerical values involves recognizing the function's definition and recalling or calculating its value at specific angles. This skill is important for solving problems where functions must be paired with correct values, often using known angle measures.
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