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Ch. 3 - Radian Measure and The Unit Circle
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161, 9780135440780, 9780136881117, 9780135440827, 9780135924891Non è quello che usi tu?Cambia libro di testo
Capitolo 4, Problema 67

Find the exact value of s in the given interval that has the given circular function value.


[π/2, π] ; sin s = 1/2

Guida verificata passo dopo passo
1
Identify the given interval for the variable \(s\), which is \(\left[\frac{\pi}{2}, \pi\right]\), and the equation \(\sin s = \frac{1}{2}\).
Recall the unit circle values where \(\sin s = \frac{1}{2}\). The sine function equals \(\frac{1}{2}\) at angles \(\frac{\pi}{6}\) and \(\frac{5\pi}{6}\) within one full rotation \([0, 2\pi]\).
Determine which of these angles lie within the given interval \(\left[\frac{\pi}{2}, \pi\right]\). Since \(\frac{\pi}{6}\) is less than \(\frac{\pi}{2}\), it is excluded, but \(\frac{5\pi}{6}\) lies within the interval.
Conclude that the exact value of \(s\) in the interval \(\left[\frac{\pi}{2}, \pi\right]\) satisfying \(\sin s = \frac{1}{2}\) is \(s = \frac{5\pi}{6}\).
Verify the solution by substituting \(s = \frac{5\pi}{6}\) back into the sine function to confirm \(\sin \left(\frac{5\pi}{6}\right) = \frac{1}{2}\).

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When solving trigonometric equations, restricting the solution to a specific interval ensures the answer fits the problem’s domain. For s in [π/2, π], only angles within this range are considered, which helps select the correct exact value of s.
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