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
5:01 minutes
Problem 3
Textbook Question
Textbook QuestionIn Exercises 1–6, use the figures to find the exact value of each trigonometric function.
tan 2θ
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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, tangent (tan) of an angle is the ratio of the opposite side to the adjacent side. Understanding these functions is essential for solving problems involving angles and distances in triangles.
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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 formula for tangent states that tan(2θ) = 2tan(θ) / (1 - tan²(θ)). These formulas are useful for simplifying expressions and solving equations involving angles that are multiples of a given angle, which is relevant for finding tan(2θ) in the given problem.
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Pythagorean Theorem
The Pythagorean theorem states that in a right triangle, 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 determining the lengths of sides when only some dimensions are known, and it can be used to find the sine, cosine, and tangent values necessary for solving trigonometric problems.
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