n. 正弦

[计] 正弦

[ noun ]
ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle
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Sine \Si"ne\, prep. [L.]
Without.


Sine \Sine\, n. [LL. sinus a sine, L. sinus bosom, used in
translating the Ar. jaib, properly, bosom, but probably read
by mistake (the consonants being the same) for an original
j[=i]ba sine, from Skr. j[=i]va bowstring, chord of an arc,
sine.] (Trig.)
(a) The length of a perpendicular drawn from one extremity
of an arc of a circle to the diameter drawn through
the other extremity.
(b) The perpendicular itself. See {Sine of angle}, below.

{Artificial sines}, logarithms of the natural sines, or
logarithmic sines.

{Curve of sines}. See {Sinusoid}.

{Natural sines}, the decimals expressing the values of the
sines, the radius being unity.

{Sine of an angle}, in a circle whose radius is unity, the
sine of the arc that measures the angle; in a right-angled
triangle, the side opposite the given angle divided by the
hypotenuse. See {Trigonometrical function}, under
{Function}.

{Versed sine}, that part of the diameter between the sine and
the arc.