arc cosine

8.8

To find the angle whose cosine equals a given number

noun
/ɑrk ˈkoʊsaɪn/

Specialized

: arco coseno

To find the angle, you need to calculate the arc cosine of the cosine value.

Examples

The calculator has a function to compute the arc cosine when provided with a cosine number.
In trigonometry, the arc cosine function helps determine angles from known cosine values.
And may I just write down what's the derivative of the arc cosine as long as we're at it and then I'm done The derivative of the arc cosine.

Synonyms

arccos

vsarc cosine

Specialized

1 9.9

An angle whose cosine equals a given number

is the same function but written in full words

arccosine

vsarc cosine

Specialized

9.9

A function that gives the angle whose cosine equals a given number

is the same function but written as two words

inverse cosine

vsarc cosine

Specialized

8.1

An angle that has a given cosine value

is the same function but usually referred to using full words rather than symbols

Surface Forms

arc cosine singular

arc cosines plural

Morphology

arc + cosine

This is a technical mathematical term where the everyday noun 'arc' (a curved shape) does not transparently signal 'inverse' to a B1 learner, so knowing 'arc' + 'cosine' would not normally let them infer 'the inverse function of the cosine'. However, within mathematical usage 'arc-' conventionally marks inverse trig functions (arccos) and relates to the angle corresponding to a curve, so there is a domain-specific, partially predictable connection.

Etymology

Arc cosine comes from geometry: arc means a part of a circle and cosine is the number you get from an angle. So arc cosine finds the 'angle' or arc that has that cosine.