subexpressions (OT: math)

[Alex Martelli]

Stebanoid at gmail.com <Stebanoid at gmail.com> wrote:

> On 3    , 22:07, "Steban... at gmail.com" <Steban... at gmail.com> wrote:
> >
> > angle is a ratio of two length and
> >dimensionless.http://en.wikipedia.org/wiki/Angle#Units_of_measure_for_ang
> >les
> >
> > only dimensionless values can be a argument of a sine and exponent!
> > Are you discordant?
> 
> if you are discordant read more :P :
> sine is a dimensionless value.
> if we expand sine in taylor series sin(x) = x - (x^3)/6 + (x^5)/120
> etc.
> you can see that sin can be dimensionless only if x is dimensionless
> too.
> 
> I am a professional physicist and a know about what I talk

Lots of people are confused by the concept of "degrees" -- your Taylor
series, of course, intrinsically assumes x is "in radians" (which of
course IS how angles "truly are").  I blame the Babylonians for that
confusion just as much as for the clunky base-60 that intrudes in our
ordinary time reckoning...!


Alex