cosine

noun
co·​sine

Definition of cosine

1 : a trigonometric function that for an acute angle is the ratio between the leg adjacent to the angle when it is considered part of a right triangle and the hypotenuse
2 : a trigonometric function cos θ that for all real numbers θ is given by the sum of the alternating series {latex}1 - \frac{x^2}{2!} + \frac{x^4}{4!} - \frac{x^6}{6!} + \frac{x^8}{8!} - \dots{/latex} and that is exactly equal to the cosine of an angle of measure θ in radians

Examples of cosine in a Sentence

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The link was so clear it could be described in derivative sines and cosines, mathematical concepts taught in college trigonometry.

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First Known Use of cosine

1635, in the meaning defined at sense 1

History and Etymology for cosine

New Latin cosinus, from co- + Medieval Latin sinus sine

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The first known use of cosine was in 1635

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More Definitions for cosine

cosine

noun

English Language Learners Definition of cosine

geometry : the ratio between the long side (called the hypotenuse) and the side that is next to an acute angle in a right triangle

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Britannica English: Translation of cosine for Arabic Speakers

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to take the place or position of

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