Question

How do you find the domain & range for `y=Arccos x`?

Answer 1

[0, `pi`]

Explanation:

When cos x varies in [`-`1, 1 ].
If cos x is positive, the angle y is in the first quadrant, [ 0, `pi`/2 ]. Otherwise, it is in the second, [ `pi`/2, `pi` ].