Numbers and Geometry

1 Arithmetic.- 1.1 The Natural Numbers.- 1.2 Division, Divisors, and Primes.- 1.3 The Mysterious Sequence of Primes.- 1.4 Integers and Rationals.- 1.5 Linear Equations.- 1.6 Unique Prime Factorization.- 1.7 Prime Factorization and Divisors.- 1.8 Induction.- 1.9* Foundations.- 1.10 Discussion.- 2 Geometry.- 2.1 Geometric Intuition.- 2.2 Constructions.- 2.3 Parallels and Angles.- 2.4 Angles and Circles.- 2.5 Length and Area.- 2.6 The Pythagorean Theorem.- 2.7 Volume.- 2.8* The Whole and the Part.- 2.9 Discussion.- 3 Coordinates.- 3.1 Lines and Circles.- 3.2 Intersections.- 3.3 The Real Numbers.- 3.4 The Line.- 3.5 The Euclidean Plane.- 3.6 Isometries of the Euclidean Plane.- 3.7 The Triangle Inequality.- 3.8* Klein’s Definition of Geometry.- 3.9* The Non-Euclidean Plane.- 3.10 Discussion.- 4 Rational Points.- 4.1 Pythagorean Triples.- 4.2 Pythagorean Triples in Euclid.- 4.3 Pythagorean Triples in Diophantus.- 4.4 Rational Triangles.- 4.5 Rational Points on Quadratic Curves.- 4.6* Rational Points on the Sphere.- 4.7* The Area of Rational Right Triangles.- 4.8 Discussion.- 5 Trigonometry.- 5.1 Angle Measure.- 5.2 Circular Functions.- 5.3 Addition Formulas.- 5.4 A Rational Addition Formula.- 5.5* Hubert’s Third Problem.- 5.6* The Dehn Invariant.- 5.7* Additive Functions.- 5.8* The Tetrahedron and the Cube.- 5.9 Discussion.- 6 Finite Arithmetic.- 6.1 Three Examples.- 6.2 Arithmetic mod n.- 6.3 The Ring ?/n?.- 6.4 Inverses mod n.- 6.5 The Theorems of Fermat and Wilson.- 6.6 The Chinese Remainder Theorem.- 6.7 Squares mod p.- 6.8* The Quadratic Character of-1 and.- 6.9* Quadratic Reciprocity.- 6.10 Discussion.- 7 Complex Numbers.- 7.1 Addition, Multiplication, and Absolute Value.- 7.2 Argument and the Square Root of -1.- 7.3 Isometries of the Plane.- 7.4 The Gaussian Integers.- 7.5 Unique Gaussian Prime Factorization.- 7.6 Fermat’s TWo Squares Theorem.- 7.7* Factorizing a Sum of Two Squares.- 7.8 Discussion.- 8 Conic Sections.- 8.1 Too Much, Too Little, and Just Right.- 8.2 Properties of Conic Sections.- 8.3 Quadratic Curves.- 8.4* Intersections.- 8.5 Integer Points on Conics.- 8.6* Square Roots and the Euclidean Algorithm.- 8.7* Pell’s Equation.- 8.8 Discussion.- 9 Elementary Functions.- 9.1 Algebraic and Transcendental Functions.- 9.2 The Area Bounded by a Curve.- 9.3 The Natural Logarithm and the Exponential.- 9.4 The Exponential Function.- 9.5 The Hyperbolic Functions.- 9.6 The Pell Equation Revisited.- 9.7 Discussion.