the differences are tiny though, and there are other measures that can be used (which will result in different constants)
in any case, on most modern hardware it is not relevant since there is some lookup based instruction that is more accurate, and faster.
the problems here aren't enormous, a smart programmer will work them out for himself, but they are misleading. i think there is some confusion just because this is a low-level API, essentially a hardware abstraction layer, but the user is expecting high level features like a complete maths library. (maybe?)