This file is from Wikimedia Commons and may be used by other projects.
The description on its file description page there is shown below.
Summary
DescriptionUnit-circle sin cos tan cot exsec excsc versin cvs.svg
English: A unit circle with sine (sin), cosine (cos), tangent (tan), cotangent (cot), versine (versin), coversine (cvs), exsecant (exsec), excosecant (excsc) and (indirectly) also secant (sec), cosecant (csc) as well as chord (crd) and arc labeled as trigonometric functions of angle theta. It is designed as alternative construction to "Circle-trig6.svg" possibly making some relations between the functions more obvious (and others less obvious). The file deliberately uses the same style and naming conventions as "Circle-trig6.svg". It was derivated from "Circle-trig6.svg" but completely reworked.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.