The word RADIAN was coined by Professor James Thomson (a
brother of Lord Kelvin). He used it as early as 1871, but it first
appeared in print on an examination he administered on
June 5, 1873, at Queens College in Belfast, Ireland (Cajori 1919,
page 484).
Radian appears in 1879 in Thomson & Tait, Nat. Phil.: "The usual
unit angle is..that which subtends at the centre of a circle an arc
whose length is equal to the radius;..for brevity we shall call this
angle a radian" (OED2).
> When students ask (not often enough) why do we need to measure angles in
> radians, I know of no other answer than it makes things very convenient in
> calculus. This is fine for my calculus students who can see what the
> derivatives of trig functions would look like without radians, but what
> other answer can I give my pre-calculus students?
>
> Does anyone know of other good reasons for using radians?
>
> Does anyone know the history of radian measure? Who first used it and why?
>
> Martin Kalmar
> Frederick Community College
> Frederick, Md.
> mkalmar@fcc.cc.md.us
>
------------------------------------------------------
Larry Husch phone:423-974-4162 fax:423-974-6576
Dept.Mathematics http://www.math.utk.edu/~husch
Univ. Tennessee Co-Director, Mathematics Archives
Knoxville, TN 37996 http://archives.math.utk.edu/
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