Discover the answers to your questions at Westonci.ca, where experts share their knowledge and insights with you. Experience the ease of finding precise answers to your questions from a knowledgeable community of experts. Join our Q&A platform to connect with experts dedicated to providing accurate answers to your questions in various fields.

Find the exact value of the expression whenever it is defined. (If an answer is undefined, enter UNDEFINED.)

(a) [tex]\arcsin \left(\sin \frac{13 \pi}{12}\right)[/tex]
[tex]\square[/tex]

(b) [tex]\arccos \left(\cos \frac{8 \pi}{5}\right)[/tex]
[tex]\square[/tex]

(c) [tex]\arctan \left(\tan \frac{5 \pi}{4}\right)[/tex]
[tex]\square[/tex]

Sagot :

To find the exact values of the given expressions, we need to evaluate some key properties of the trigonometric and inverse trigonometric functions involved. Let's go through each part step-by-step:

### (a) \(\arcsin(\sin(\frac{13\pi}{12}))\)
The function \(\arcsin(x)\) yields a value within the interval \([- \frac{\pi}{2}, \frac{\pi}{2}]\). We need to find the principal value of the angle equivalent to \(\frac{13\pi}{12}\) within this interval.

1. \(\frac{13\pi}{12}\) is greater than \(\pi/2\), so we need to find an equivalent angle within \([- \frac{\pi}{2}, \frac{\pi}{2}]\).
2. Consider the sine function's property: \(\sin(\theta) = \sin(\pi - \theta)\).
3. Notice that \(\frac{13\pi}{12} = \pi + \frac{\pi}{12}\). Thus, its sine is \(\sin(\frac{13\pi}{12}) = \sin(\pi - (-\frac{\pi}{12})) = -\sin(\frac{\pi}{12})\).

Therefore, the principal value is:
[tex]\[ \arcsin(\sin(\frac{13\pi}{12})) = -\frac{\pi}{12} \][/tex]

In decimal form, this is approximately:
[tex]\[ \boxed{-0.26179938779914946} \][/tex]

### (b) \(\arccos(\cos(\frac{8\pi}{5}))\)
The function \(\arccos(x)\) yields a value within the interval \([0, \pi]\). We need to find the principal value of the angle equivalent to \(\frac{8\pi}{5}\) within this interval.

1. \(\frac{8\pi}{5}\) is greater than \(\pi\), so we need to find an equivalent angle within \([0, \pi]\).
2. Consider the cosine function's property: \(\cos(\theta) = \cos(2\pi - \theta)\).
3. \(\frac{8\pi}{5} = 2\pi - \frac{2\pi}{5}\). This angle can be converted to the equivalent angle in \([0, \pi]\) by subtracting one full period (\(2\pi\)):
[tex]\[ \frac{8\pi}{5} = 2\pi - \frac{2\pi}{5} \Rightarrow \frac{2\pi}{5} \][/tex]

Therefore, the principal value is:
[tex]\[ \arccos(\cos(\frac{8\pi}{5})) = \frac{2\pi}{5} \][/tex]

In decimal form, this is approximately:
[tex]\[ \boxed{1.2566370614359175} \][/tex]

### (c) \(\arctan(\tan(\frac{5\pi}{4}))\)
The function \(\arctan(x)\) yields a value within the interval \([- \frac{\pi}{2}, \frac{\pi}{2}]\). We need to find the principal value of the angle equivalent to \(\frac{5\pi}{4}\) within this interval.

1. \(\frac{5\pi}{4}\) is beyond \(\pi/2\), so we need to find an equivalent angle within \([- \frac{\pi}{2}, \frac{\pi}{2}]\).
2. Consider the tangent function's property for \(\frac{5\pi}{4}\):
[tex]\[ \frac{5\pi}{4} = \pi + \frac{\pi}{4} \][/tex]

Since \(\tan(\theta) = \tan(\theta + n\pi)\) where \(n\) is an integer, the tangent value for this angle is:
[tex]\[ \tan(\frac{5\pi}{4}) = \tan(\frac{\pi}{4}) \][/tex]
But because it's actually in the third quadrant, the tangent value is negative, and:
[tex]\[ -\arctan(\tan(\frac{\pi}{4})) = -\frac{\pi}{4} \][/tex]

Therefore, the principal value is:
[tex]\[ \arctan(\tan(\frac{5\pi}{4})) = -\frac{\pi}{4} \][/tex]

In decimal form, this is approximately:
[tex]\[ \boxed{0.7853981633974482} \][/tex]
Thank you for your visit. We're committed to providing you with the best information available. Return anytime for more. We appreciate your time. Please revisit us for more reliable answers to any questions you may have. Discover more at Westonci.ca. Return for the latest expert answers and updates on various topics.