id: 05948947
dt: j
an: 2011f.00018
au: Bressoud, David M.
ti: Historical reflections on teaching trigonometry.
so: Math. Teach. (Reston) 104, No. 2, 106-112 (2010).
py: 2010
pu: National Council of Teachers of Mathematics (NCTM), Reston, VA
la: EN
cc: A30 G60
ut: elementary algebra; trigonometry; history of mathematics education;
measurement; geometric concepts; computation
ci:
li: http://www.nctm.org/eresources/article_summary.asp?URI=MT2010-09-106a&from=B
ab: Summary: The study of trigonometry suffers from a basic dichotomy that
presents a serious obstacle to many students. On the one hand, there is
triangle trigonometry, in which angles are commonly measured in degrees
and trigonometric functions are defined as ratios of sides of a
right-angled triangle. On the other hand, there is circle trigonometry,
in which angles are commonly measured in radians and trigonometric
functions are expressed in terms of the coordinates of a point on the
unit circle centered at the origin. Faced with two such distinct
conceptual approaches to trigonometry, is it any wonder that so many
students get confused? Once students begin to use the sine and cosine
as examples of periodic functions, circle trigonometry dominates, but
there is a tradition that triangle trigonometry is the simpler and more
basic form and that students need to be grounded in this before being
introduced to circle trigonometry. This article provides a historical
overview of the development of trigonometry. This historical overview
presents an argument for beginning the study of trigonometry with the
circle definitions of the trigonometric functions and angle
measurement. (Contains 18 figures.) (ERIC)
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