The core author of the book's first activity, [b]Pre Activity: Trigonometric Functions in Region[/b], is [b]Jesus Perez[/b]. Additionally, we completed the applet by adding [b]dynamic check boxes [/b]and writing [b]instructions[/b] for the GeoGebra activity.

File:Sin x = sin (180- x) and cos (180- x) = -cos x.png[br][url=https://commons.wikimedia.org/wiki/File:Sin_x_%3D_sin_%28180-_x%29_and_cos_%28180-_x%29_%3D_-cos_x.png]https://commons.wikimedia.org/wiki/File:Sin_x_%3D_sin_%28180-_x%29_and_cos_%28180-_x%29_%3D_-cos_x.png[/url][br]"This file is licensed under the [url=https://en.wikipedia.org/wiki/en:Creative_Commons]Creative Commons[/url] [url=https://creativecommons.org/licenses/by-sa/4.0/deed.en]Attribution-Share Alike 4.0 International[/url] license."

The remaining parts of the book were made by authors Hafsa Metin and Esma Nur Karaca.