# What is Calculus? From Simple Algebra to Deep Analysis

###### R. Michael Range
Publisher:
World Scientific
Publication Date:
2016
Number of Pages:
340
Format:
Paperback
Price:
38.00
ISBN:
9789814644488
Category:
Textbook
BLL Rating:

The Basic Library List Committee suggests that undergraduate mathematics libraries consider this book for acquisition.

[Reviewed by
P. N. Ruane
, on
03/22/2016
]

The approach to differentiation in this book begins with Descartes’s thoughts on ‘double points on algebraic curves’ (which he used to construct normals and their associated tangents). This technique leads to a definition of differentiability that avoids limits of the type $0/0$. In the simplest case, the tangent to the graph of a polynomial $P$ at the point $(a, P(a))$ is a line that intersects the graph of $P$ with multiplicity greater than or equal to 2. The unique line satisfying this condition has slope $q(a)$, where $q$ is the polynomial determined by the factorisation $P(x) - P(a) = q(x)(x - a)$.

This idea pervades all material in opening chapter, which is called ‘Prelude to Calculus’. In the context of algebraic functions (mainly polynomials), the notion of derivative clearly emerges, and the basic rules of differentiation are initially derived within this limited context.

Ideas on real analysis first appear in the following chapter, where number systems are studied with respect to cardinality and completeness. Transcendental functions are revised and concepts of local and global boundedness are introduced.

Great emphasis is subsequently placed upon techniques for measuring ‘rates of change’ so that, half way through the book, readers will be ready to digest Carathéodory’s more general definition of differentiability:

A function $f$ defined in a neighbourhood of a point $a \in \mathbb{R}$ is differentiable at $a$ if there exists a factorisation $f(x) - f(a) = q(x)(x - a),$ where $q$ is continuous at $x=a$.

The value $q(a)$ is called the derivative of $f$ at $a$ and is denoted by $D(f)(a)$ or $f'(a)$.

In addition to bypassing limits of the sort $0/0$, other claimed advantages of this formulation are that it provides easier proofs of the chain rule and the inverse function rule — and it is also said to generalize more naturally to multivariable calculus. However, there is no use of Leibniz notation and the concept of ‘differential’ isn’t crystallised within these pages.

On the other hand, local numerical linear approximation is the context in which differentiability, limits and continuity are more rigorously examined. Throughout the book, real analysis is seen to serve the needs of calculus which, in turn, is shown to have many real-world applications. There are many examples, illustrations and useful exercises (no solutions provided), so this makes the book an ideal text for its stated purpose.

As for the book’s ‘stated purpose’, Michael Range says that:

…it could be used as a text for an honors class with well motivated students, where the instructor has flexibility in adjusting course content.
…could also be used as a text in a first course on real analysis.

Having enjoyed reading this book, I feel that it may not be first choice for use with students who are new to calculus; but it certainly would provide excellent a corrective revision of calculus for those who have been taught it simplistically. It also represents an imaginative (and less rarefied) introduction, to real analysis, because ideas on real analysis only appear when they illuminate particular aspects of calculus under discussion.

Another attractive feature of the book is its historical element, which includes reference to the algebraic/geometric method of Apollonius for finding tangents; the work of Galileo on falling bodies; the methods of Newton, Leibniz and Cantor’s notions of cardinality. This, together with the above-mentioned features, make this book a uniquely imaginative introduction to real analysis alongside a cogent account of the principles, and applications, of differentiation and the Riemann integral.

Peter Ruane’s reading on calculus began with Teach Yourself Calculus (P. Abbot, 1940) and continued in numerous stages to Spivak’s Calculus on Manifolds and it is now rounded off nicely by the book under this review.

• Prelude to Calculus:
• Introduction
• Tangents to Circles
• Tangents to Parabolas
• Motion with Variable Speed
• Tangents to Graphs of Polynomials
• Rules for Differentiation
• More General Algebraic Functions
• Beyond Algebraic Functions
• The Cast: Functions of a Real Variable:
• Real Numbers
• Functions
• Simple Periodic Functions
• Exponential Functions
• Natural Operations on Functions
• Algebraic Operations and Functions
• Derivatives: How to Measure Change:
• Algebraic Derivatives by Approximation
• Derivatives of Exponential Functions
• Differentiability and Local Linear Approximation
• Properties of Continuous Functions
• Derivatives of Trigonometric Functions
• Simple Differentiation Rules
• Product and Quotient Rules
• Some Applications of Derivatives:
• Exponential Models
• The Inverse Problem and Antiderivatives
• "Explosive Growth" Models
• Acceleration and Motion with Constant Acceleration
• Periodic Motions
• Geometric Properties of Graphs
• An Algorithm for Solving Equations
• Applications to Optimization
• Higher Order Approximations and Taylor Polynomials
• The Definite Integral:
• The Inverse Problem: Construction of Antiderivatives
• The Area Problem
• More Applications of Definite Integrals
• Properties of Definite Integrals
• The Fundamental Theorem of Calculus
• Existence of Definite Integrals
• Reversing the Chain Rule: Substitution
• Reversing the Product Rule: Integration by Parts
• Higher Order Approximations, Part 2: Taylor's Theorem
• Excursion into Complex Numbers and the Euler Identity