versed sine
Contents
English[edit]
Etymology[edit]
From New Latin sinus versus (“flipped sine”); the sine function being sometimes called sinus rectus.
Noun[edit]
versed sine (plural versed sines)
 (trigonometry) The trigonometric function 1 − cos(x).
 1753, John Robertson, The Construction of the Logarithmic Lines on the Gunter′s Scale, Royal Society (Great Britain), Philosophical Transactions: 17501755, page 340,
 For the divisions, to be laid on this line, are the differences between the logarithm versed sine of 180°, and the logarithm versed sines of the successive arcs.
 1805, John William Norie, A New and Complete Epitome of Practical Navigation, page xxii,
 But if the given arch exceed 90°, find the natural cosine of its supplement, which add to 1000000, and the sum will be the natural versed sine required.
 1806, John Garnett, Tables Requisite To Be Used with The Nautical Ephemeris, page 41,
 The Natural Sines in this table are fractions (radius being unit); and are particularly adapted to Dunthorne′s and other methods of clearing the moon′s distance from the effects of parallax and refraction, where natural sines or versed sines are used ; […] .
 1753, John Robertson, The Construction of the Logarithmic Lines on the Gunter′s Scale, Royal Society (Great Britain), Philosophical Transactions: 17501755, page 340,
Usage notes[edit]
Once considered an important trigonometric function; now much less so, since the advent of calculators and computers.
Synonyms[edit]
Derived terms[edit]
Translations[edit]
function 1 − cos

