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Ch. 3 - Trigonometric Identities and Equations
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Not the one you use?Change textbook
Chapter 3, Problem 24

Use one or more of the six sum and difference identities to solve Exercises 13–54. In Exercises 13–24, find the exact value of each expression. tan ( 5𝝅/3 οΉ£ 𝝅/4)

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1
Identify the given expression: \(\tan\left( \frac{5\pi}{3} - \frac{\pi}{4} \right)\).
Recall the tangent difference identity: \(\tan(A - B) = \frac{\tan A - \tan B}{1 + \tan A \tan B}\).
Set \(A = \frac{5\pi}{3}\) and \(B = \frac{\pi}{4}\), then find \(\tan A\) and \(\tan B\) separately.
Calculate \(\tan \frac{5\pi}{3}\) and \(\tan \frac{\pi}{4}\) using known values or reference angles.
Substitute these values into the tangent difference formula and simplify the resulting expression step-by-step.

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Key Concepts

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

Sum and Difference Identities for Tangent

These identities express the tangent of a sum or difference of two angles in terms of the tangents of the individual angles. Specifically, tan(A - B) = (tan A - tan B) / (1 + tan A * tan B). This formula is essential for breaking down complex tangent expressions into simpler parts.
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Exact Values of Trigonometric Functions at Special Angles

Certain angles like Ο€/3, Ο€/4, and Ο€/5 have known exact trigonometric values involving square roots and rational numbers. Knowing these values allows for precise calculation without approximations, which is crucial when solving problems requiring exact answers.
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Simplification of Trigonometric Expressions

After applying identities, simplifying the resulting expressions by combining like terms, rationalizing denominators, or reducing fractions is necessary. This step ensures the final answer is in its simplest exact form, which is often required in trigonometry exercises.
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