Re: Sin Cos Tan, why not Sin Sec Tan?

From: Narasimham G.L. (mathma18_at_hotmail.com)
Date: 07/17/04 

Date: 17 Jul 2004 11:39:15 -0700

jdolan@math-cl-n03.math.ucr.edu (James Dolan) wrote in message news:<cd716d$sji$1@glue.ucr.edu>...
> in article <nomjc.1663$K53.873@news-server.bigpond.net.au>,
> cassandra thompson <cass.harley@bigpond.com> wrote:
...

> the name "trigonometry" suggests that the subject is all about
> triangles, but that's very misleading; what trigonometry secretly
> _really_ is is the study of the points on the unit circle. ...

The word is derived from Sanskrit. Tri- for three, Gono- for Kona or
angle,(gonio-meter for angle measurement) metry from Matra or
measure or unit. Essentially angular rotation is measured in the
first step, as ratios of side lengths around the triangle.

To drive this home, teaching of sin/cos/tan should be done
simultaneously or concurrently with the definition of a radian, as 2
Pi radians for one full rotation, as the central wedge angle of sector
of a circle.