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

Find the exact value of each real number y. Do not use a calculator.
y = tan⁻¹ (―√3)

검증된 단계별 안내
1
Recognize that the problem asks for the exact value of \(y = \tan^{-1}(-\sqrt{3})\), which means we need to find an angle \(y\) whose tangent is \(-\sqrt{3}\).
Recall the basic angles where tangent values are known: \(\tan(\frac{\pi}{3}) = \sqrt{3}\) and \(\tan(-\frac{\pi}{3}) = -\sqrt{3}\). These angles are commonly used in trigonometry and correspond to 60° and -60°, respectively.
Since the inverse tangent function \(\tan^{-1}(x)\) returns values in the interval \(\left(-\frac{\pi}{2}, \frac{\pi}{2}\right)\) (or \((-90^\circ, 90^\circ)\)), the angle \(y\) must lie within this range.
Identify that \(y = -\frac{\pi}{3}\) is the angle in the principal range of \(\tan^{-1}\) such that \(\tan(y) = -\sqrt{3}\).
Therefore, the exact value of \(y\) is \(-\frac{\pi}{3}\), which corresponds to \(-60^\circ\) in degrees.

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.

Inverse Tangent Function (arctan)

The inverse tangent function, denoted as tan⁻¹ or arctan, returns the angle whose tangent is a given number. It maps real numbers to angles typically in the range (-π/2, π/2). Understanding this helps find the angle y such that tan(y) equals the given value.
추천 영상:
3:17
Inverse Tangent

Exact Values of Tangent for Special Angles

Certain angles have well-known exact tangent values, such as π/6, π/4, and π/3. For example, tan(π/3) = √3 and tan(π/6) = 1/√3. Recognizing these values allows one to identify the angle corresponding to a given tangent without a calculator.
추천 영상:
6:04
Example 1

Sign and Quadrant Considerations for arctan

Since tan⁻¹ returns angles in (-π/2, π/2), negative tangent values correspond to negative angles in this interval. For tan⁻¹(-√3), the angle is negative and matches the reference angle where tangent is √3, ensuring the correct sign and quadrant are chosen.
추천 영상:
6:36
Quadratic Formula