> sqrt and log that work for bignums whenever possible.
 > ...
 > exact-integer-log, similar to exact-integer-sqrt, for completeness

I think sqrt on bignums should be handled by exact-integer-sqrt.

I like the idea of exact-integer-log, but doing that in general sounds
like I have to transform the radix of the number. (I don't have the
energy or time to write that implementation right now.)

 > trigonometric functions that work with bignums

This might be too difficult to mandate.

___________________________

 > This reminds me that Gambit has integer-nth-root (should really be
called exact-integer-nth-root), but without a remainder:

This is also in CHICKEN (same algorithm) and the implementation is not
too complicated. I might add it.

-- Peter McGoron