Dave wrote:
"Jim Kelley" wrote in message
...

Cecil Moore wrote:


Sorry Jim, but [Io*cos(kx)*cos(wt)] and [Io*cos(kx+wt)] *ARE*
different.

Evidently, you can't recognize a trig identity when you see one.


in my book
cos(a+b)=cos(a)cos(b)-sin(a)sin(b)
so cos(kx+wt) would expand to:
cos(kx)cos(wt)-sin(kx)sin(wt)
me thinks you are missing a few terms in your 'identity'.

I'm sure your book is correct, Dave. Mine probably is too. (It has
CRC Standard Mathematical Tables printed on the cover.) Cecil through
a curve ball. The correct function for a standing wave can be written
as the algebraic sum of two sine functions, or as the product of a
sine and a cosine function e.g. y = 2*Ymax*sin(kx)cos(wt).

73, ac6xg