'(float)"-nan"' doesn't return Indet in LSL:
llOwnerSay(llList2CSV([(float)"-nan"])); // outputs "nan", not "-nan"
Therefore, for the output to yield the correct result we have to use a different strategy to generate an indeterminate. We choose '(1e40*0)' which is shorter than the rest.
Also, we don't output infinites as '(float)"[-]inf"' but alwas as '1e40' or '(float)-1e40' (or just '-1e40' if we're in globals).