# cosine

mathematics

**Learn about this topic** in these articles:

### function in trigonometry

- In trigonometry
…and abbreviations are sine (sin), cosine (cos), tangent (tan), cotangent (cot), secant (sec), and cosecant (csc). These six trigonometric functions in relation to a right triangle are displayed in the figure. For example, the triangle contains an angle

Read More*A*, and the ratio of the side opposite to*A*and the…

### work of Euler

- In mathematics: History of analysis
…introduction of the sine and cosine functions. Trigonometry tables had existed since antiquity, and the relations between sines and cosines were commonly used in mathematical astronomy. In the early calculus mathematicians had derived in their study of periodic mechanical phenomena the differential equationand they were able to interpret its solution

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