(1) The range for asin and acos is shown as bounded inclusively by
mathematical Pi/2, and that for atan (and atan2) as bounded but
excluding those endpoints. Yet in most FP formats Pi/2 is not
an FP number, so what does that mean? Is the endpoint of a
result maximally PI/2 (Math Pi/2 rounded down), or can it be
Pi/2 rounded up?
This issue becomes acute when converting an interval to one
using a wider base format, because at that point new FP numbers
come into existence that should be included (or excluded) from
the interval. Given general containment rules I suppose the
range should be defined by outward rounding.