standard_description: Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output. (Function notation is not required in Grade 8.)
problem_activity: Find two values where
$${\mathrm{cos}x=-1}$$
.
What is
$${\mathrm{arccos}(-1)}$$
?


aligns: no