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Ch. 1 - Angles and the Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Non è quello che usi tu?Cambia libro di testo
Capitolo 1, Problema 10

In Exercises 9–16, use the given triangles to evaluate each expression. If necessary, express the value without a square root in the denominator by rationalizing the denominator.
Right triangle PQR with angles 30° and 60°, sides labeled 1, 2, and √3.
tan 30°

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Identify the sides relative to the 30° angle in the triangle. The side opposite the 30° angle is QR, which has length 1. The side adjacent to the 30° angle is PQ, which has length \( \sqrt{3} \).
Recall the definition of the tangent function: \( \tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} \). For \( \theta = 30^\circ \), this becomes \( \tan 30^\circ = \frac{\text{opposite side}}{\text{adjacent side}} \).
Substitute the lengths of the sides into the tangent ratio: \( \tan 30^\circ = \frac{1}{\sqrt{3}} \).
Since the denominator contains a square root, rationalize the denominator by multiplying numerator and denominator by \( \sqrt{3} \): \( \tan 30^\circ = \frac{1}{\sqrt{3}} \times \frac{\sqrt{3}}{\sqrt{3}} = \frac{\sqrt{3}}{3} \).
Thus, the expression for \( \tan 30^\circ \) is simplified and rationalized as \( \frac{\sqrt{3}}{3} \).

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