Sine and cosine

Fundamental trigonometric functions

In mathematics, sine and cosine are trigonometric functions. The sine and cosine of an acute angle are defined in the context of a right triangle: the sine of an acute angle of a right triangle is the ratio of the length of the side opposite that angle to the length of the longest side of the triangle, the hypotenuse; the cosine is the ratio of the length of the adjacent side to that of the hypotenuse. For an angle θ {\displaystyle \theta } , the sine and cosine functions are denoted as sin ⁡ ( θ) {\displaystyle \sin(\theta)} and cos ⁡ ( θ) {\displaystyle \cos(\theta)} .

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