Deep Learning, Ian Goodfellow, Yoshua Bengio, and Aaron Courville, 2016 (MIT Press) - Foundational textbook on deep learning. Chapter 4 discusses numerical computation, applying multivariable calculus to cost functions and optimization.
Multivariable Calculus (18.02SC), Denis Auroux, 2010 (Massachusetts Institute of Technology) - A free online course from MIT providing a structured introduction to multivariable calculus, including functions and their visualization.