Saveliev, Peter Calculus Illustrated. Volume 1: Precalculus (1677752521)
Mathematical thinking is visual. The exposition in this book is driven by its illustrations; there are over 600 of them.Calculus is hard. Many students are too late to discover that they could have used a serious precalculus course. The book is intended for self-study and includes only the topics that are absolutely unavoidable.This is the first volume of the series Calculus Illustrated. The book's website hosts the drafts of volumes 2-5.