"Bob Wilson" wrote in message
...
On 2/16/2016 12:31 AM, Sal M. O'Nella wrote:
"gareth" wrote in message ...
Some texts give wavenumber as radians per metre, whereas others give
it as cycles per metre, for a propagating wave over a distance.
Which is preferred?
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My recollections for formulae is that most use radians. Lower case
omega is angular velocity in radian/sec. Divide by 2-pi for Hz, I
believe.
I have not seen all of the earlier discussion. But: If you are going to
plug the results into trig functions (sine, tangent, etc.) or expect to
get them from inverse trig functions, the usual trig functions are more
conveniently used with radians. Any other units require "fudge factors"
like 180/Pi. So that is a reason on the radians side.
(Is that called a fiddle factor on other side of the big pond?)

I was digging around for the formula for a travelling wave
and encountered cos(kx-wt), where k is the wave number and
w the radians/sec, which thinking further means that k HAS to
be radians per metre and not cycles per metre.