Calculus: Early Transcendentals, James Stewart, 2015 (Cengage Learning) - A standard and widely used textbook that provides fundamental definitions of functions, their notation, types, and properties, essential for calculus beginners.
Pattern Recognition and Machine Learning, Christopher M. Bishop, 2006 (Springer)DOI: 10.1007/b137979 - A classic textbook that systematically introduces the mathematical foundations of machine learning, including the role of functions as models and objective functions.
Deep Learning, Ian Goodfellow, Yoshua Bengio, and Aaron Courville, 2016 (MIT Press) - Provides a comprehensive overview of the mathematical concepts underlying deep learning, starting with foundational topics like functions and their application in machine learning models and optimization.
18.01SC Single Variable Calculus, David Jerison, Arthur Mattuck, Haynes Miller, Benjamin Brubaker, Jeremy Orloff, Heidi Burgiel, Christine Breiner, David Jordan, Joel Lewis, 2010 (MIT OpenCourseWare) - Offers a structured, university-level introduction to single variable calculus, covering the fundamental definitions, types, and behavior of functions in detail.