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
Introduction to Trigonometric Identities
Problem 5.42a
Textbook Question
Each expression simplifies to a constant, a single function, or a power of a function. Use fundamental identities to simplify each expression.
1/ tan² α + cot α tan α
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1
Recognize that \( \tan \alpha = \frac{\sin \alpha}{\cos \alpha} \) and \( \cot \alpha = \frac{\cos \alpha}{\sin \alpha} \).
Rewrite \( \frac{1}{\tan^2 \alpha} \) as \( \cot^2 \alpha \) using the identity \( \cot \alpha = \frac{1}{\tan \alpha} \).
Substitute \( \cot^2 \alpha \) for \( \frac{1}{\tan^2 \alpha} \) in the expression.
Simplify \( \cot \alpha \tan \alpha \) to 1, since \( \cot \alpha = \frac{1}{\tan \alpha} \).
Combine the simplified terms: \( \cot^2 \alpha + 1 \).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Trigonometric Identities
Trigonometric identities are equations that involve trigonometric functions and are true for all values of the variables involved. Fundamental identities, such as the Pythagorean identities, reciprocal identities, and quotient identities, are essential for simplifying trigonometric expressions. Understanding these identities allows students to manipulate and transform expressions effectively.
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Reciprocal Functions
Reciprocal functions in trigonometry refer to the relationships between sine, cosine, tangent, and their reciprocals: cosecant, secant, and cotangent. For example, the tangent function is the reciprocal of cotangent, and this relationship is crucial when simplifying expressions. Recognizing these relationships helps in rewriting expressions in a more manageable form.
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Secant, Cosecant, & Cotangent on the Unit Circle
Simplification Techniques
Simplification techniques in trigonometry involve rewriting complex expressions into simpler forms using identities and algebraic manipulation. This may include factoring, combining like terms, or substituting equivalent expressions. Mastering these techniques is vital for solving trigonometric equations and understanding their behavior in various contexts.
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Example 6
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