The inverse sine function
can only operate on numbers in the domain of
.
For the given function
, the only restriction is that
, which you must solve to find that the domain is actually
or, in interval notation,
.
Had the question asked for the domain of
, you would have needed to solve
to get a domain of
.
Finally, had the question asked for the domain of
, you would still have needed to solve
but subject to the additional constraint that
, producing a domain of
.