# Definition of *cofunction* in English:

## cofunction

### Pronunciation /ˈkōˌfəNG(k)SH(ə)n/ /ˈkoʊˌfəŋ(k)ʃ(ə)n/

### noun

Mathematics

The trigonometric function of the complement of an angle or arc.

*‘Similarly, tan x and cot x are cofunctions of each other, and sec x and csc x are cofunctions of each other.’*

*‘Students will be able to use reciprocals, quotients, Pythagorean identities, cofunctions, and composite-arguments to prove trig identities.’**‘The question wants an angle less than 45º, so we use our cofunctions.’**‘Students will learn how to write a function in terms of its cofunction or how to solve for an angle given a cofunction equality.’**‘There will be a sheet of formulas for trig functions: double and half-angle, cofunctions, addition and subtraction, sum and product.’*