In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side … 展开

Unit circle definition
The sine and cosine functions may also be defined in a more general way by using unit circle, a … 展开

Etymology
The word sine is derived, indirectly, from the Sanskrit word jyā 'bow-string' or more specifically its synonym jīvá (both adopted from Ancient … 展开

There is no standard algorithm for calculating sine and cosine. IEEE 754, the most widely used standard for the specification of reliable … 展开

Right-angled triangle definition
To define the sine and cosine of an acute angle $${\displaystyle \alpha }$$, start with a right triangle that contains an angle of measure $${\displaystyle \alpha }$$; in the accompanying figure, angle $${\displaystyle \alpha }$$ 展开

Complex exponential function definitions
Both sine and cosine can be extended further via complex number, a set of numbers composed of both real and imaginary numbers. … 展开

• Āryabhaṭa's sine table
• Bhaskara I's sine approximation formula
• Discrete sine transform
• Dixon elliptic functions
• Euler's formula 展开