Question

Dewight needs to restrict the domain of the cosine function so that the inverse is a function. Which description best describes how she could restrict the domain?
A) So that y = cos(x) is always decreasing
B) So that y = cos(x) only has one maximum
C) So that y = cos(x) only has one minimum <<my answer
D) So that y = cos(x) only has two maximum

Answer 1

you don't want any maxima or minima, because that means the graph bends back on itself, meaning it fails the horizontal-line test.

(A) is what you want. the domain is [0,pi]