cosine

co·sine

the reciprocal of the secant; specif.

the ratio of the adjacent side of a given acute angle in a right triangle to the hypotenuse
an equivalent, positive or negative ratio for certain related angles (Ex.: the cosine of 57° or 303° is .5446, of 123° or 237° is ?.5446) or real numbers representing radians (Ex.: cosine of .9948 radians (57°) is .5446)

Origin of cosine

Modern Latin from co. sinus, short for complementi sinus, literally , sine of the complement

cosine

noun

Abbr. cos

In a right triangle, the ratio of the length of the side adjacent to an acute angle to the length of the hypotenuse.
The abscissa at the endpoint of an arc of a unit circle centered at the origin of a Cartesian coordinate system, the arc being of length x and measured counterclockwise from the point (1, 0) if x is positive or clockwise if x is negative.

cosine

cosine

cos &thgr; = ^b_c

cosine

Noun

(plural cosines)

(trigonometry) In a right triangle, the ratio of the length of the side adjacent to an acute angle to the length of the hypotenuse. Symbol: cos

Usage notes

In various branches of mathematics, the cosine of an angle is determined in various ways, including the following:

The x-coordinate of the point on the unit circle at the given anticlockwise angle from the x-axis.
The sum of the real or complex power series where x is in radians.

Anagrams

cosine - Computer Definition

See sine.

SentencesSentence examples

Sentence Examples

Since dr/ds is the cosine of the angle between the directions of r and ~s.
For mercury in a glass tube the angle of contact is 128° 52', the cosine of which is negative.
In considering the relative brightnesses of the different spectra, it is therefore sufficient to attend merely to the principal directions, provided that the whole deviation be not so great that its cosine differs considerably from unity.
C2P2=IC2cos obliquity (The obliquity which is found to answer best in practice is about 143/4; its cosine is about i3/4, and its sine about 3/4.
Consequently, one of the forms suitable for the teeth of wheels is the involute of a circle; and the obliquity of the action of such teeth is the angle whose cosine is the ratio of the radius of their base-circle to that of the pitch-circle of the wheel.

Also Mentioned In

Words near cosine in the dictionary