# Media credits for Unit 22 {#agc-media-credits-unit-22}

The seven substantive media positions in Lecture 22 and Worksheet 22
retain the identities, attributions, and licensing routes of their source
components. The two official PDFs are authority/build witnesses, not
additional reader media positions.

1. **Tangent to a curve** — [File:Tangent to a curve.svg](https://commons.wikimedia.org/wiki/File:Tangent_to_a_curve.svg); creator according to the current Commons record: Jacj, with later versions by Oleg Alexandrov; rights status: public domain.
2. **Three lines meeting at one point** — [File:3 equations -5.JPG](https://commons.wikimedia.org/wiki/File:3_equations_-5.JPG); creator: Cronholm144; rights status: public domain.
3. **Portrait of René Descartes** — [File:Frans Hals - Portret van René Descartes.jpg](https://commons.wikimedia.org/wiki/File:Frans_Hals_-_Portret_van_Ren%C3%A9_Descartes.jpg); work after Frans Hals, reproduction source as recorded by Commons; rights status: public domain.
4. **Folium of Descartes** — [File:Kartesisches-Blatt.svg](https://commons.wikimedia.org/wiki/File:Kartesisches-Blatt.svg); creator: Georg-Johann; licensing route used: [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/).
5. **Two curve components intersecting at a triple point** — [File:Intersect3.png](https://commons.wikimedia.org/wiki/File:Intersect3.png); creator: Michael Larsen; licensing route used through GFDL migration on Commons: [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/).
6. **A tangent to a circle is perpendicular to the radius** — [File:Cercle tangente rayon.svg](https://commons.wikimedia.org/wiki/File:Cercle_tangente_rayon.svg); original work: Christophe Dang Ngoc Chan (Cdang), SVG conversion/derivative: Hagman; licensing route used: [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/).
7. **Cardioid** — [File:Cardioid.svg](https://commons.wikimedia.org/wiki/File:Cardioid.svg); creator: D.328; reuse route displayed by Commons: [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/), with the raw GFDL/CC BY-SA 2.1 JP and migration records retained in the rights ledger.

Reconciliation note: the inline Wikiversity credit for the tangent image
names `AxelBoldt`, whereas the frozen Commons description names Jacj and
Oleg Alexandrov. Commons component metadata governs attribution in this
edition; the differing Wikiversity label is retained as provenance in the
freeze, not republished as an authorship fact. Raw dual-licensing and
migration records for the four licensed components are retained in
`authority/RIGHTS-unit-22.csv`; the edition makes no blanket-licence claim
for the mixed collection.

Both official PDFs contain internal CC BY-SA 3.0 boilerplate, whereas the
frozen current course and Commons records identify both as CC BY-SA 4.0
components. The edition retains this difference as provenance. The
translated text remains under CC BY-SA 4.0. Translation, checking, and
production of the edition were assisted by
**OpenAI Codex gpt-5.6-sol, Ultra.**