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Cosine
From OeisWiki
The cosine of an angle , denoted as , is one of the most important [circular] trigonometric functions.
Given the angle of an arc on a unit circle, is the length of the side on a right triangle going along a line along (the other two sides being a side opposing a vertex coinciding with the center of the circle and hypotenuse).
- (PLACEHOLDER FOR IMAGE) ^{[1]}
Per the Pythagorean theorem, .
The following graph shows the sine and cosine functions graphed together (sine is in red, cosine in blue):
Taylor series expansion
The Taylor series expansion of the cosine function is
Formulae
(...)
See also
- For the decimal expansions of the cosine of 89 to 1 degrees, see Sine#Table of sine and cosine values.
- {{cos}} mathematical function template
Notes
- ↑ Provide illustration.