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Ch. 6 - Inverse Circular Functions and Trigonometric Equations
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161당신이 사용하는 게 아니라요?교과서 변경
7장, 문제 15

Solve each equation for exact solutions over the interval [0, 2π).
2 cot x + 1 = ―1

검증된 단계별 안내
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Start by isolating the cotangent term in the equation: 2 \(\cot\) x + 1 = -1. Subtract 1 from both sides to get 2 \(\cot\) x = -2.
Divide both sides of the equation by 2 to solve for \(\cot\) x: \(\cot\) x = \(\frac{-2}{2}\) = -1.
Recall that \(\cot\) x = \(\frac{\cos x}{\sin x}\). The equation \(\cot\) x = -1 means \(\frac{\cos x}{\sin x}\) = -1, or equivalently, \(\cos\) x = -\(\sin\) x.
Rewrite the equation as \(\cos\) x + \(\sin\) x = 0. To find exact solutions, consider the unit circle or use the identity \(\tan\) x = \(\frac{\sin x}{\cos x}\). Since \(\cot\) x = -1, then \(\tan\) x = -1.
Find all values of x in the interval [0, 2\(\pi\)) where \(\tan\) x = -1. These correspond to angles where the tangent function equals -1, typically in the second and fourth quadrants.

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주요 개념

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

Cotangent Function and Its Properties

The cotangent function, cot x, is the reciprocal of the tangent function, defined as cot x = cos x / sin x. It is periodic with period π and undefined where sin x = 0. Understanding cotangent's behavior and domain restrictions is essential for solving equations involving cot x.
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Introduction to Cotangent Graph

Solving Trigonometric Equations

Solving trigonometric equations involves isolating the trigonometric function and finding all angles within the given interval that satisfy the equation. This often requires algebraic manipulation and using inverse trigonometric functions, while considering the function's periodicity to find all solutions.
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How to Solve Linear Trigonometric Equations

Interval Notation and Solution Sets

When solving trigonometric equations, solutions are often restricted to a specific interval, such as [0, 2π). Understanding how to express solutions within this interval and how to handle periodicity ensures that all valid solutions are identified and correctly reported.
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i & j Notation