To: J3                                                     J3/24-124
From: Malcolm Cohen
Subject: Trigonometric function spelling
Date: 2024-May-31
References: 24-007


1. Introduction

It has been pointed out that arc cosine is sometimes spelled arccosine,
i.e. with no space between the two words. ISO terminology has the space.

Similarly for arcsine and arctangent.

There is also "arccos(X)", "arcsin(X)", and "arctan(X)".
These should be written out as text rather than pseudo-maths.


2. Edits to 24-007

[throughout]
Change all "arccosine" to "arc cosine".
Change all "arcsine" to "arc sine".
Change all "arctangent" to "arc tangent".

[ACOS, ASIN, ATAN, ATAN2]
Change the only "arccos(X)" to "the arc cosine of X".
Change the only "arcsin(X)" to "the arc sine of X".
Change "arctan(X)" to "the arc tangent of X",
and change "arctan(Y/X)" to "the arc tangent of Y/X".
In these changes, if a comma is then warranted in the sentence, insert one.

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