The implied domain: the real x-values for which the function is valid.

The range: The possible y values that the function can take.

a)

Firstly, we know that in any situation,

The arcsin function takes the value obtained for and generates the value.

If then

So, as

Is only defined for

To find the range then. You know that the minimum value obtained for and the maximum for

So

Not entirely certain on this but that was my attempt!