Trig function names: math history?

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Discussion Overview

The discussion centers on the historical origins and naming conventions of trigonometric functions, specifically the terms sin, cos, csc, sec, and others. Participants explore the implications of these names on understanding and remembering the functions, as well as their usage in mathematical contexts.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions the naming conventions of trigonometric functions, suggesting that it would be easier if cos was defined as 1/sin and csc as 1/sec, similar to cot being 1/tan.
  • Another participant provides a link to historical context, indicating that the notations were developed for simplification rather than arbitrary reasons.
  • A different viewpoint expresses frustration with the additional terms (csc, sec, cot), arguing that they complicate the learning process and are rarely encountered in practice.
  • One participant explains that the prefix "co" in cosine and cotangent relates to their definitions involving complementary angles, asserting that this naming is reasonable.

Areas of Agreement / Disagreement

Participants express differing opinions on the usefulness and necessity of the additional trigonometric terms. There is no consensus on whether the historical naming conventions are beneficial or complicate understanding.

Contextual Notes

Some assumptions about familiarity with trigonometric functions and their applications may not be shared among all participants. The discussion does not resolve the complexities surrounding the use of these terms in different contexts.

EnumaElish
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Does anyone know how the function names sin, cos, csc, sec, ... came about?

Wouldn't they be easier to remember if cos was 1/sin; csc was 1/sec; just like cot is 1/tan? (Instead of 1/sin = csc and 1/cos = sec.)

This is one thing in trig that always throws me off.
 
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Probably a read of this link would help you appreciate the usage of these words,
http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Trigonometric_functions.html

Note that these notations came out of necessity (for simplification) and not through a magic wand :smile:

-- AI
 
Bah. Here we just learn sin, cos and tan. Period.
Why use extra terms (csc, sec cot) for 1/sin etc. You hardly encounter them anywhere anyway. Trig is complicated enough with all the relations among sin, cos and tan. It's only making it more complicated.
 
The "co" is from the fact that the cosine is the sine of the complementary angle (90 degrees minus θ- the other angle in the right triangle). Same for cotangent, cosecant. Perfectly reasonable.
 

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