In Exercises 55–58, use a calculator to find the value of the acute angle θ to the nearest degree. sin θ = 0.2974
Table of contents
- 0. Review of College Algebra4h 45m
- 1. Measuring Angles40m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
1. Measuring Angles
Angles in Standard Position
Problem 99
Textbook Question
Find two values of θ, 0 ≤ θ < 2𝜋, that satisfy each equation.
sin θ = √2/2
Verified step by step guidance1
Recall the range of the sine function: \(\sin \theta\) can only take values between \(-1\) and \$1\(. Since \(\frac{\sqrt{2}}{2}\) is approximately \)0.707$, it is within this range, so solutions exist.
Recognize that \(\sin \theta = \frac{\sqrt{2}}{2}\) corresponds to a well-known angle in the unit circle. Identify the reference angle \(\alpha\) such that \(\sin \alpha = \frac{\sqrt{2}}{2}\).
From the unit circle, the reference angle \(\alpha\) is \(\frac{\pi}{4}\) because \(\sin \frac{\pi}{4} = \frac{\sqrt{2}}{2}\).
Since sine is positive in the first and second quadrants, find the two angles \(\theta\) in \([0, 2\pi)\) where \(\sin \theta = \frac{\sqrt{2}}{2}\). These are \(\theta = \alpha\) and \(\theta = \pi - \alpha\).
Write the two solutions explicitly as \(\theta = \frac{\pi}{4}\) and \(\theta = \pi - \frac{\pi}{4}\), which simplifies to \(\theta = \frac{3\pi}{4}\).
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
2mPlay a video:
0 Comments
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Unit Circle and Angle Measurement
The unit circle is a circle with radius 1 centered at the origin, used to define trigonometric functions for all angles. Angles are measured in radians from 0 to 2π for one full rotation, which helps identify the sine values corresponding to specific angles.
Recommended video:
Introduction to the Unit Circle
Sine Function Values and Their Range
The sine function outputs values between -1 and 1. Knowing that sin θ = √2/2 corresponds to specific standard angles (π/4 and 3π/4) within the interval 0 ≤ θ < 2π is essential for finding solutions.
Recommended video:
Domain and Range of Function Transformations
Finding Multiple Solutions in One Period
Since sine is positive in the first and second quadrants, there are two angles between 0 and 2π where sin θ equals √2/2. Understanding the symmetry of sine values in these quadrants allows identification of both solutions.
Recommended video:
Introduction to Cotangent Graph
Related Videos
Related Practice
Textbook Question
609
views
