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Ch. 5 - Trigonometric Identities
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161당신이 사용하는 게 아니라요?교과서 변경
6장, 문제 2

Match each expression in Column I with its value in Column II.
(2 tan 15°)/(1 - tan² 15°)

검증된 단계별 안내
1
Recognize that the given expression \( \frac{2 \tan 15^\circ}{1 - \tan^2 15^\circ} \) matches the double-angle formula for tangent, which is \( \tan 2\theta = \frac{2 \tan \theta}{1 - \tan^2 \theta} \).
Identify \( \theta = 15^\circ \) in the expression, so the expression simplifies to \( \tan 2 \times 15^\circ = \tan 30^\circ \).
Recall the exact value of \( \tan 30^\circ \), which is a well-known special angle in trigonometry.
Use this value to match the expression from Column I with the corresponding value in Column II.
Confirm the match by verifying the angle and the formula used, ensuring the correct pairing.

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주요 개념

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Tangent Double-Angle Formula

The tangent double-angle formula states that tan(2θ) = (2 tan θ) / (1 - tan² θ). This identity allows us to express the tangent of twice an angle in terms of the tangent of the original angle, simplifying calculations involving angle multiples.
추천 영상:
05:06
Double Angle Identities

Properties of the Tangent Function

The tangent function relates an angle in a right triangle to the ratio of the opposite side over the adjacent side. It is periodic with period 180°, and understanding its behavior and values at special angles like 15° is essential for evaluating expressions.
추천 영상:
5:43
Introduction to Tangent Graph

Angle Measurement and Conversion

Angles can be measured in degrees or radians, and recognizing common angle values such as 15°, 30°, and 45° helps in applying trigonometric identities. Accurate angle measurement is crucial for correctly using formulas and matching expressions to their values.
추천 영상:
5:31
Reference Angles on the Unit Circle