Question

The domain of f(x)=cosx

must be restricted to all real numbers in order for the function to have an inverse function. The domain of g(x)=arccos(x)
is −1≤x≤1
and its range is 0≤x≤π
.
is this correct ?

Answer 1

Not completely sure for the rest, but I believe the range is incorrect: the range represents y-values, not x-values.

So it should be 0 ≤ y ≤ π