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A trigonometric function used in connection with right triangles; best seen as a ratio of side lengths.

In basic trigonometry, it is used to determine unknown side lengths or an acute angle measurement(s). In more advanced mathematics, cosine is treated simply as a function without an apparent or direct reference to a triangle (the triangle's presence becomes assumed). Examples of this may be seen in Calculus through the process of integration. Wherein, the function cosine may only be a part of a large equation.

Cosine is one component out of a three-part acronym known as: SOHCAHTOA. The term cosine occupies the "CAH," wherein the series forms: Cosine (equals) Adjacent (over) Hypotenuse.
Cosine thus represents the ratio of the Adjacent side length to the Hypotenuse side length -- this is all in relation to an (acute) angle, theta.

When dealing with an angle measurement, x ("theta"), the side "touching" the angle is referred to as the Adjacent side; the side furthest away from the angle is referred to as the Opposite side; and, in a right triangle, the hypotenuse always remains and, simplistically, may be recognized as the diagonal side.

In mathematical procedures, cosine is abbreviated as "cos" for convenience.

Note: UrbanDictionary entries do not support Entity, Hex or Decimal browser rendering. This definition replaces the Greek small letter, "theta", with an "x."
However, in reality, it appears as an "o" or a "zero" with a line going horizontally through the center.
1. Cosine = Adjacent / Hypotenuse

2. Sine / Cosine = Tangent

3. 'the integral of' 2x cos(3x) dx

cosine by HB <3 SA August 29, 2008
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"Cosine 30 is the square root of 0.75, not 0.5!! That's sine
cosine by jiexi December 8, 2003
Related Words
this word originates from this joke as it sounds like cousin

QWhat did one gangster mathmetician say to the other mathmetitian

A "sup cosine"
me and my mates call each other cosine instaid of cousin
Cosine by Bill-Dizzle December 5, 2010
See 0.999847741
cosine by xaiydehn@yahoo.com July 2, 2004
This is the girl that Kingblunted100 simps for daily
Cosine it is time for your daily simping from kingblunted100
Cosine by CEO Of Chicken Nuggies November 2, 2020

I saw the cosine 

"I saw the sign" for trigonometry geeks.
I saw the cosine, and it opened up my eyes, I saw the cosine.
I saw the cosine by KEMMA SLAY June 26, 2016
A coiner is someone who compulsively buys ticket refills in Rebel Racing.
-"Dude, that portuguese guy just joined my h2h bracket and he already has 900 points! I hate these coiners!"
-"Yeah, I know, he does that every time... he just can’t help but paying to win. Last time he did over 4k points in my bracket!"
Coiner by Tina-turner July 4, 2021
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