Chronology of Updates

Note: I have placed chronology of updates for 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 and 2007 into separate files. Starting with 1997, the most recent entries appear topmost. Besides providing an insight into this site's evolution, chronology of updates may be used for word searches.

December 31 MacLaurin's Construction of Conics
December 26 Chasles' Theorem, a Simple Proof
December 25 What Is Ellipse?
December 25 Focus and Directrix of Ellipse
December 25 Focal Definition of Ellipse
December 24 Conjugate Diameters in Ellipse
December 22 Bisector of an imaginary angle may be real
December 21 Angle Bisectors in Ellipse II
December 20 Infinite Discent for x4 + y4 = z4
December 20 Ellipse Between Two Circles
December 19 Pairs of Homologous Lines under Spiral Similarities
December 17 No-Pedal Collinearity
December 17 Angle Bisectors in Ellipse
December 17 Spiral Similarity
December 16 Fermat's Little Theorem
December 16 Pencils of Cubics
December 16 Three Tangents, Three Chords in Ellipse
December 15 Urquhart's Theorem For And By Conics
December 12 Miquel's Theorem for Circles
December 12 SixPoints, ThreeLines
December 10 Thébault's Problem IV
December 9 Homologous Lines under Three Spiral Similarities
December 7 Derivatives without Limits
December 7 Sum without Adding
December 7 Stereographic Projection and Inversion
December 6 Proof #80 of the Pythagorean theorem
December 5 Product Of Four Consecutive Integers
December 2 Cubic Formula
November 25 Morley's Theorem: Proof by B. Stonebridge and B. Millar
November 24 Regular Polyhedra: Tetrahedron, Octahedron, Cube, Icosahedron, Dodecahedron
November 23 Nested Radicals
November 23 Monotone Convergence Theorem
November 22 Possible or Impossible?
November 19 Given Parabola, Find Axis
November 19 Parallel Chords in Ellipse
November 18 Pedal Collinearities
November 17 Two Simsons in a Triangle
November 17 Infinite Rod
November 16 Generalization That Solves the Problem
November 9 What Is Symmetry?
October 30 What Is Percent?
October 28 A Market Day
October 27 Review of The Princeton Companion to Mathematics
October 26 The Many Ways to Construct a Triangle IV
October 22 Newton's Method by Newton
October 19 Newton's Method
October 18 Four Touching Circles III
October 17 Four Touching Circles II
October 13 Riemann Sphere and Möbius Transformation
October 8 Stereographic Projection of a Coffin Problem
October 4 Stereographic Projection and Radical Axes
October 4 Bevan's Point and Theorem
October 3 What Is Abstraction?
October 2 Shearing Butterflies in Quadrilaterals
October 1 Construction of a Triangle from the Circumcenter, Orthocenter and Incenter
September 22 Review of Kiselev's Geometry: Book II. Stereometry
Septembe 21 Fermat point and 9-point Centers
Septembe 21 Principle of Proportionality
Septembe 20 120° Breeds 90°
Septembe 20 Four Centroids and Parallels
September 18 Graph and Roots of a Third Degree Polynomial
September 17 Graph and Roots of Quadratic Polynomial
September 16 Completing a Square and Quadratic Formula
September 13 Why a Diameter Is the Longest Chord?
September 12 Projective infinity
September 11 Infinity in Compactification
September 10 Five Concyclic Points
September 9 6 to 9 Point Circle
September 7 Y. Sawayama's Theorem
September 6 Circles Tangent to Circumcircle
September 5 Geometric Proof of Wilson's Theorem
September 3 Divisibility and Modulo Arithmetic at IMO 2007
September 3 Proof #79 of the Pythagorean Theorem
September 2 A Clique of Acquaintances
September 2 Round Robin Tournament
August 29 Bulls and Cows, Vowel Movement, Thugs and Bowmen
August 26 Triangles with Equal Area, Solutions 5 and 6
August 26 Angle Bisector in Parallelogram
August 25 Triangles with Equal Area, Solutions 2, 3, 4
August 24 Triangles with Equal Area
August 22 Six Concyclic Points
August 21 Circles through the Orthocenter
August 15 Two Intersecting Circles
August 14 Concyclic Points in Equilateral Bumps
August 13 Review of Arithmetic for Parents: A Book for Grownups about Children's Mathematics by R. Aharoni
August 8 Diameters and Chords
August 8 A Line in Triangle Through the Circumcenter
July 30 Geometric Construction of Roots of Quadratic Equation
July 24 How to Ask an Embarrassing Question
July 23 Review of Dr. Euler's Fabulous Formula: Cures Many Mathematical Ills by P. Nahin
July 22 Review of Duelling Idiots and Other Probability Puzzlers by P. Nahin
July 21 What Is Limit?
July 18 Surreal Numbers
July 14 Review of The Mathematician's Brain by David Ruelle
July 11 What Is Algorithm?
July 10 What Is Calculus?
July 9 Review of The Calculus Gallery: Masterpieces from Newton to Lebesgue by William Dunham
July 2 Right Replacement
June 27 Butterfly in Ellipse
June 25 Shaggy Dog Theorem
June 24 Proofreading Example
June 23 Binomial Distribution
June 22 Bernoulli Trials
June 19 Pinning Butterfly on Radical Axes
June 10 Algorithm for Computing LCM
June 7 Cantor-Bernstein-Schroeder theorem
June 5 Gergonne and Soddy Lines Are Perpendicular
June 3 Chess Players Truel
June 3 Weitzenböck Inequality
June 1 Ordinal Numbers
May 30 Order. Well-ordered sets.
May 28 Cardinal Numbers
May 21 Review of A Course in the Geometry of n Dimensions
May 13 Infinity As a Limit
May 12 Projective Generalization of Maxwell's Theorem
May 11 Projective Proof of Maxwell's Theorem
May 10 What Is Infinity?
May 8 3-4-5 Triangle by a Kid
May 7 Bayes' Theorem
May 6 Trigonometric Functions
May 6 What Is Trigonometry?
May 5 The Lepidoptera of the Quadrilateral II
May 5 3D Quadrilateral - a Coffin Problem
May 5 Maxwell Theorem via the Center of Gravity
May 2 Japanese Art and Mathematics
May 1 A Sangaku by a Teen
May 1 Review of Sacred Mathematics: Japanese Temple Geometry
May 1 Peacock's Tail Sangaku
April 30 Circles and Semicircles in Rectangle
April 30 Four Hinged Squares
April 28 Neuberg Sangaku
April 25 What Is Analytic Geometry?
April 25 Guessing Two Consecutive Integers
April 24 A Certain Ambiguity
April 22 Sangaku with Three Mixtilinear Circles
April 16 Continuous Sample Spaces
April 15 Conditional Probability and Independent Events
April 10 Square in Chair
April 9 E. W. Dijkstra's Proof of the Pythagorean Theorem
April 6 Paper Folding & Cutting Sangaku
April 3 Gion Shrine Problem
April 3 A 49th Degree Challenge
April 2 Another simple integral
March 31 Vecten's Mesh
March 29 Touching Circles and Concurrency
March 28 Pappus' Generalization of Euclid I.47
March 23 Isoperimetric Theorem for Rectangles
March 17 Sangaku: Critique of My View and a Response
March 17 Construction of a Triangle from Two Vertices and the Centroid
March 2 Another proof of irrationality of N
March 2 Boys and Girls Solving Problems
February 25 Huygens' proof of the Pythagorean Theorem
February 21 Three Congruent Circles by Reflection III
February 20 Fermat's Point, Solution #7
February 19 Fermat's Point, Solution #6
February 18 Gergonne in Ellipse
February 17 Seven Circles Theorem
February 13 Expectation
February 10 A Hard but Important Sangaku
February 6 Fundamental Theorem of Algebra - Yet Another Proof
February 2 Concyclic Points in a Triangle
January 29 Two Congruent Circles by Reflection
January 27 Independent Events and Independent Experiments
January 26 Fuss' Theorem
January 26 Intouch Triangle in Poncelet Porism
January 26 Extouch Triangle in Poncelet Porism
January 25 Euler's Formula and Poncelet Porism
January 22 Three Congruent Circles by Reflection II
January 21 Three Congruent Circles by Reflection
January 12 Zeros and Nines
January 8 Random Variables
January 7 Chevalier de Méré's Problem
January 6 Dependent and Independent Events
January 5 Conditional Probability
January 4 Geometric view of the Sieve of Eratosthenes
January 1 Pythagorean Theorem: J. Adams' Proof by Dissection

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