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Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 7, Problema 7.6.11

Find the values in Exercises 9–12.
11. tan(arcsin(-1/2))

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Recognize that the expression is \( \tan(\arcsin(-\frac{1}{2})) \). Here, \( \arcsin(-\frac{1}{2}) \) represents an angle \( \theta \) such that \( \sin(\theta) = -\frac{1}{2} \).
Let \( \theta = \arcsin(-\frac{1}{2}) \). Since \( \sin(\theta) = -\frac{1}{2} \), we want to find \( \tan(\theta) \). Recall that \( \tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)} \).
Use the Pythagorean identity to find \( \cos(\theta) \): \( \cos(\theta) = \pm \sqrt{1 - \sin^2(\theta)} = \pm \sqrt{1 - \left(-\frac{1}{2}\right)^2} = \pm \sqrt{1 - \frac{1}{4}} = \pm \sqrt{\frac{3}{4}} = \pm \frac{\sqrt{3}}{2} \).
Determine the correct sign of \( \cos(\theta) \) by considering the range of \( \arcsin \), which is \( \left[-\frac{\pi}{2}, \frac{\pi}{2}\right] \). In this interval, cosine is positive for angles where sine is negative, so \( \cos(\theta) = \frac{\sqrt{3}}{2} \).
Finally, compute \( \tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)} = \frac{-\frac{1}{2}}{\frac{\sqrt{3}}{2}} = -\frac{1}{\sqrt{3}} \).

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