Skip to main content
Ch. 1 - Trigonometric Functions
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 82

Give all six trigonometric function values for each angle θ. Rationalize denominators when applicable. See Examples 5–7.
csc θ = ―3 , and cos θ > 0

검증된 단계별 안내
1
Identify the given information: \( \csc \theta = -3 \) and \( \cos \theta > 0 \). Recall that \( \csc \theta = \frac{1}{\sin \theta} \), so use this to find \( \sin \theta \).
Calculate \( \sin \theta \) by taking the reciprocal of \( \csc \theta \): \( \sin \theta = \frac{1}{\csc \theta} = \frac{1}{-3} = -\frac{1}{3} \).
Determine the quadrant of \( \theta \) using the signs of \( \sin \theta \) and \( \cos \theta \). Since \( \sin \theta < 0 \) and \( \cos \theta > 0 \), \( \theta \) lies in the fourth quadrant.
Use the Pythagorean identity \( \sin^2 \theta + \cos^2 \theta = 1 \) to find \( \cos \theta \). Substitute \( \sin \theta = -\frac{1}{3} \) and solve for \( \cos \theta \), choosing the positive root because \( \cos \theta > 0 \).
Find the remaining trigonometric functions using the definitions: \( \tan \theta = \frac{\sin \theta}{\cos \theta} \), \( \cot \theta = \frac{1}{\tan \theta} \), \( \sec \theta = \frac{1}{\cos \theta} \), and rationalize denominators where necessary.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
도움이 되었나요?

주요 개념

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

Reciprocal Trigonometric Functions

The six trigonometric functions include sine, cosine, tangent, cosecant, secant, and cotangent. Cosecant (csc θ) is the reciprocal of sine (sin θ), so if csc θ = -3, then sin θ = -1/3. Understanding these reciprocal relationships is essential to find all function values.
추천 영상:
6:04
Introduction to Trigonometric Functions

Sign of Trigonometric Functions in Quadrants

The sign of trigonometric functions depends on the quadrant where the angle θ lies. Given csc θ = -3 (sin θ negative) and cos θ > 0 (cosine positive), θ must be in the fourth quadrant. Knowing quadrant signs helps determine the correct values and signs of all functions.
추천 영상:
6:36
Quadratic Formula

Pythagorean Identity and Rationalizing Denominators

The Pythagorean identity sin²θ + cos²θ = 1 allows calculation of unknown function values once one is known. After finding cos θ, tangent and other functions can be derived. Rationalizing denominators ensures answers are in simplified, standard form, improving clarity and precision.
추천 영상:
2:58
Rationalizing Denominators