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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 75

Find the exact values of s in the given interval that satisfy the given condition.


[0 , 2π) ; cos² s = 1/2

Guida verificata passo dopo passo
1
Start with the given equation: \(\cos^{2} s = \frac{1}{2}\).
Take the square root of both sides to solve for \(\cos s\): \(\cos s = \pm \sqrt{\frac{1}{2}}\).
Simplify the square root: \(\cos s = \pm \frac{\sqrt{2}}{2}\).
Recall the unit circle values where \(\cos s = \pm \frac{\sqrt{2}}{2}\), which correspond to angles \(s = \frac{\pi}{4}, \frac{3\pi}{4}, \frac{5\pi}{4}, \frac{7\pi}{4}\) within the interval \([0, 2\pi)\).
List these values as the exact solutions for \(s\) in the given interval.

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To solve equations like cos²(s) = 1/2, one must first find cos(s) = ±√(1/2) = ±√2/2. Then, determine all angles s in the given interval where cosine equals these values. This involves using inverse cosine functions and considering all solutions within the specified domain.
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