Table of contents
- 0. Review of College Algebra4h 43m
- 1. Measuring Angles39m
- 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
6. Trigonometric Identities and More Equations
Double Angle Identities
2:40 minutes
Problem 4
Textbook Question
Textbook QuestionIn Exercises 1–6, use the figures to find the exact value of each trigonometric function.
sin 2α
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Trigonometric Functions
Trigonometric functions relate the angles of a triangle to the lengths of its sides. The primary functions include sine, cosine, and tangent, which are defined as ratios of the sides of a right triangle. For example, in a right triangle, the sine of an angle is the ratio of the length of the opposite side to the hypotenuse. Understanding these functions is essential for solving problems involving angles and side lengths.
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Double Angle Formulas
Double angle formulas are trigonometric identities that express trigonometric functions of double angles in terms of single angles. For instance, the sine double angle formula states that sin(2α) = 2sin(α)cos(α). These formulas are useful for simplifying expressions and solving equations involving trigonometric functions, particularly when calculating values for angles that are multiples of a given angle.
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Pythagorean Theorem
The Pythagorean theorem is a fundamental principle in geometry that relates the lengths of the sides of a right triangle. It states that the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides. This theorem is crucial for finding missing side lengths in trigonometric problems and for verifying the relationships between the sides of a triangle.
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