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Ch. 5 - Trigonometric Identities
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161Not the one you use?Change textbook
Chapter 6, Problem 44

Simplify each expression. See Example 4.
tan 34°/2(1 - tan² 34°)

Verified step by step guidance
1
Recognize that the expression resembles the double-angle formula for tangent. Recall the formula: \(\tan(2\theta) = \frac{2 \tan \theta}{1 - \tan^2 \theta}\).
Compare the given expression \(\frac{\tan 34^\circ}{2(1 - \tan^2 34^\circ)}\) with the double-angle formula. Notice that the numerator and denominator are arranged differently.
Rewrite the given expression to see if it can be manipulated into the form of the double-angle formula. For example, consider multiplying numerator and denominator appropriately or factoring to match the formula's structure.
Use the double-angle identity to express \(\tan 68^\circ\) in terms of \(\tan 34^\circ\) and relate it back to the given expression.
Conclude the simplification by substituting the equivalent double-angle expression, which will simplify the original expression into a single tangent function or a simpler trigonometric expression.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Tangent Double-Angle Identity

The tangent double-angle identity expresses tan(2θ) in terms of tan(θ): tan(2θ) = 2 tan(θ) / (1 - tan²(θ)). This identity helps simplify expressions involving tangent of multiple angles by rewriting them in terms of a single angle.
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Algebraic Simplification of Trigonometric Expressions

Simplifying trigonometric expressions often involves factoring, combining like terms, and applying identities. Recognizing patterns such as the double-angle formula allows rewriting complex fractions into simpler forms.
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Understanding how to evaluate or manipulate trigonometric functions at given angles, like 34°, is essential. This includes knowing approximate values or using identities to rewrite expressions for easier calculation or simplification.
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