Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
0. Functions
Inverse Trigonometric Functions
Problem 78
Textbook Question
Evaluating inverse trigonometric functions Without using a calculator, evaluate the following expressions.
csc−1(−1)
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1
Understand that \( \csc^{-1}(x) \) is the inverse cosecant function, which gives the angle \( \theta \) such that \( \csc(\theta) = x \).
Recall that \( \csc(\theta) = \frac{1}{\sin(\theta)} \). Therefore, \( \csc^{-1}(-1) \) means we are looking for an angle \( \theta \) where \( \sin(\theta) = -1 \).
The sine function \( \sin(\theta) \) equals \(-1\) at specific angles. Consider the unit circle: \( \sin(\theta) = -1 \) at \( \theta = \frac{3\pi}{2} \) (or \( 270^\circ \)).
Verify that \( \theta = \frac{3\pi}{2} \) is within the range of the inverse cosecant function. The principal range for \( \csc^{-1}(x) \) is \([-\frac{\pi}{2}, \frac{\pi}{2}] \) excluding \( 0 \), but for negative values, we consider angles in the third and fourth quadrants.
Conclude that the angle \( \theta = \frac{3\pi}{2} \) satisfies the condition \( \csc(\theta) = -1 \), and thus \( \csc^{-1}(-1) = \frac{3\pi}{2} \).
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