Question: Three argument signum

Does anybody mind clarifying what the three argument signum means?

I have the expression


in which z>0, R>0. I guess I know what signum means, however in this case according to the help it is considering signum of 0 and then in the help it is talking about some environment variable. I just dont quite understand...

Does it mean Maple has issues to clarify the sign of R-sqrt(R^2+z^2) ??


Please Wait...