State (i) the implied domain and (ii) the range of each of the following.

a) $\displaystyle y=sin^{-1}(x^2)$

b) $\displaystyle y=tan^{-1}(2x)$

c) $\displaystyle y=tan^{-1}(4-x)$

d) $\displaystyle y=cos^{-1}(x^2-1)$

I don't know how to do all of the above. What are the steps for undertaking the processes?

Perhaps someone can explain and then attempt one or two and then I could try to do the rest and they someone else could check whether it's right or wrong?

Anyway, whatever the case, how do you do the above?

Any help/guidance to do the above will be appreciated!