Precalculus

Precalulus is studied before the study of calculus. These include topics such as functions, trigonometry, and algebraic concepts. Precalculus is designed to prepare you for the study of calculus by introducing and reinforcing important mathematical concepts and principles. Through your study of precalculus, you will gain a deeper understanding of mathematical concepts and principles, and you will be better able to apply these principles to real-world situations.

For reference

Precalculus: An Investigation of Functions (2nd Ed)

https://archive.org/details/MITRES.18-008