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RE: supplementary S.I. units



On Fri, 25 Sep 1998, Donald E. Simanek wrote:

On Fri, 25 Sep 1998, George Spagna wrote:

At 09:05 AM 9/25/98 -0400, Donald E. Simanek wrote:

sin(theta) and tan(theta) approach theta radians in the limit as theta
goes to zero. Not so if theta is measured in degrees.

Oops - don't think you meant that the way it came out. Sine and tangent
approach zero as theta approaches zero, no matter which set of units are
used for theta. The size of the domain of theta over which the
approximation works well is certainly better in radians!


Yep, careless use of the words "in the limit". Should have said "As theta
gets small.

I assure you that I wouldn't be this pedantic in class, but in this venue
it may serve some pedagogical purpose to point out that you should also
have said "... approach (theta/radian) ..." This since theta has units
and sin(theta) and tan(theta) do not. For instance, (2.3 degrees/radian)
= 0.04014 and sin(2.3 degrees) = 0.04013.

BTW, "theta radians" would have dimensions of solid angle wouldn't it?

;-)

John
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