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 15

Give the degree measure of θ. Do not use a calculator.
θ = arcsin (―√3/2)

검증된 단계별 안내
1
Recall that \(\theta = \arcsin\left(-\frac{\sqrt{3}}{2}\right)\) means we are looking for an angle \(\theta\) whose sine value is \(-\frac{\sqrt{3}}{2}\).
Identify the reference angle by considering the positive value \(\frac{\sqrt{3}}{2}\). From common special angles, \(\sin 60^\circ = \frac{\sqrt{3}}{2}\), so the reference angle is \(60^\circ\).
Since the sine value is negative, determine in which quadrants sine is negative. Sine is negative in Quadrants III and IV.
The range of the arcsin function is \([-90^\circ, 90^\circ]\) (or \([-\frac{\pi}{2}, \frac{\pi}{2}]\)), which corresponds to angles in Quadrants IV and I. Because the sine is negative, the angle must be in Quadrant IV within this range.
Therefore, the angle \(\theta\) is the negative of the reference angle, so express \(\theta\) as \(-60^\circ\).

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 Sine Function (arcsin)

The inverse sine function, arcsin, returns the angle whose sine value is a given number. It is defined for inputs between -1 and 1 and outputs angles in the range of -90° to 90° (or -π/2 to π/2 radians). Understanding arcsin helps find the angle θ when sin(θ) is known.
추천 영상:
4:03
Inverse Sine

Sine Values of Special Angles

Certain angles have well-known sine values, such as 30°, 45°, and 60°. For example, sin(60°) = √3/2. Recognizing these values allows you to identify the angle corresponding to a given sine value without a calculator.
추천 영상:
5:08
Sine, Cosine, & Tangent of 30°, 45°, & 60°

Sign and Quadrant Considerations for Inverse Trigonometric Functions

Since arcsin outputs angles only in the first and fourth quadrants, a negative sine value indicates an angle in the fourth quadrant (between -90° and 0°). This helps determine the correct angle measure for negative sine values like -√3/2.
추천 영상:
4:28
Introduction to Inverse Trig Functions