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Ch. 3 - Trigonometric Identities and Equations
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 3.3.47

In Exercises 47–54, use the figures to find the exact value of each trigonometric function. sin(θ/2)

검증된 단계별 안내
1
Identify the given angle \( \theta \) and the trigonometric function you need to find. In this case, it appears you need to find \( \sin \left( \frac{\theta}{2} \right) \), which is the sine of half the angle \( \theta \).
Recall the half-angle identity for sine: \[ \sin \left( \frac{\theta}{2} \right) = \pm \sqrt{ \frac{1 - \cos \theta}{2} } \] This formula allows you to find the sine of half an angle if you know \( \cos \theta \).
Determine the sign (positive or negative) of \( \sin \left( \frac{\theta}{2} \right) \) based on the quadrant where \( \frac{\theta}{2} \) lies. Remember that sine is positive in the first and second quadrants and negative in the third and fourth quadrants.
Find or calculate \( \cos \theta \) from the given figure or information. This might involve using the Pythagorean theorem if the figure provides side lengths, or using other trigonometric relationships.
Substitute the value of \( \cos \theta \) into the half-angle formula and simplify the expression under the square root. This will give you the exact value of \( \sin \left( \frac{\theta}{2} \right) \) up to the sign determined earlier.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Trigonometric Functions

Trigonometric functions like sine, cosine, and tangent relate the angles of a right triangle to the ratios of its sides. Understanding how to identify and calculate these ratios is essential for finding exact values of these functions for a given angle.
추천 영상:
6:04
Introduction to Trigonometric Functions

Unit Circle and Angle Measures

The unit circle is a circle with radius 1 centered at the origin, used to define trigonometric functions for all angles. Knowing how to interpret angles on the unit circle helps in finding exact trigonometric values without a calculator.
추천 영상:
06:11
Introduction to the Unit Circle

Exact Values of Common Angles

Certain angles like 0°, 30°, 45°, 60°, and 90° have well-known exact trigonometric values. Memorizing or deriving these values allows for precise calculation of trigonometric functions without approximation.
추천 영상:
3:47
Introduction to Common Polar Equations