On Wed, Apr 8, 2009 at 2:44 AM, Robert Kern <robert.k...@gmail.com> wrote: > > On Tue, Apr 7, 2009 at 15:18, flyeng4 <flye...@gmail.com> wrote: > >> In [40]: 1/s >> Out[40]: 1/s <-- Makes sense but might be 'hz'? > > You need to be careful with that. Hz specifically means "cycles per > second", which is not always the same thing as 1/s. In particular, > angular frequencies are also measured in 1/s (technically radians/s > but radians are a ratio of distances and so are "unitless" by the > usual logic), but they differ from Hz by a factor of 2*pi. Sadly, > units are not the most rigorous of mathematical constructs.
I disagree, 1/s is the definition of the hertz, period (pun accidental :-). Frequencies and angular frequencies differ by a factor 2*pi precisely because they measure different things, so equating them is (usually) an error, like equating meters and kilometers. The inability of dimensional analysis to prevent such errors is a limit of scope, not one of rigor. Fredrik --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---
