Question

1. explain the meaning of $y = \cos^{-1}x$. (1 point)
2. true or false: $\sec^{-1}0.5$ is undefined. explain your answer. (1 point)

Explanation:

Answer:

$y = \cos^{-1}x$ is the inverse cosine function, which gives the angle $y$ in the interval $[0, \pi]$ such that $\cos y = x$, where $x \in [-1, 1]$.
True. $\sec^{-1}0.5$ is undefined because $\sec\theta = \frac{1}{\cos\theta}$, so $\sec^{-1}x$ requires $|x| \geq 1$, and $0.5 < 1$.