Chronology of Updates

Note: I have placed chronology of updates for 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 and 2008 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.

Dec 30 Building Bridges
Dec 29 Join Circles by Given Segment
Dec 23 Review of Prime Curios: The Dictionary of Prime Number Trivia
Dec 21 Is .999... = 1? A Non-standard View
Dec 17 Problem 4, 1975 USA Math Olympiad: The Final Touch
Dec 15 Two Circles and Two More
Dec 14 Secant, Normal, Tangent
Dec 12 Two Circles and One More
Dec 11 Problem 4, 1975 USA Math Olympiad: Normals and Tangents
Dec 11 Problem 4, 1975 USA Math Olympiad and Isosceles Triangles
Dec 9 Rabbits Reproduce; Integers Don't
Dec 9 Four Weighings Suffice
Dec 9 All Powers of x are Constant
Nov 28 Problem 4, 1975 USA Math Olympiad and the Radical Axis
Nov 26 Changing Colors II
Nov 25 Long Up Short Down
Nov 25 Sums Of Successive Squares
Nov 21 What Is Absolute Value?
Nov 20 Make It All Zeros
Nov 18 GCD and LCM via Factoring
Nov 17 Euclid's Algorithm: An Interactive Illustration
Nov 17 Factoring with the Factor Tree
Nov 14 Compare Fractions: Interactive Practice
Nov 12 Nested Subsets
Nov 12 Napoleon's Theorem: A third proof with complex numbers
Nov 11 Shifting Digits and a Point of View
Nov 11 Tangent as a Radical Axis
Nov 10 APMO 1995 Problem 3
Nov 10 The Size is in the Eyes of the Beholder
Nov 9 Base (Binary, Decimal, etc.) Converter
Nov 8 Ambassadors at a Round Table
Nov 7 USA 1975 Problem 4
Nov 5 Importance of the Absolute Value
Nov 4 APMO 2002 Problem 3
Nov 4 USA 1975 Problem 3
Nov 2 Archimedes' Law of the Lever
Oct 31 Sine of a Sum Formula
Oct 30 Addition and Subtraction Formulas for Sine and Cosine II
Oct 30 Addition and Subtraction Formulas for Sine and Cosine
Oct 29 Chasing Angles in Pascal's Hexagon
Oct 28 Theorems of Ceva and Menelaus, an Illustrated Generalization
Oct 27 Simultaneous Generalization of the Theorems of Ceva and Menelaus
Oct 26 Trigonometric Proof of the Pythagorean Theorem
Oct 25 Escher's Theorem
Oct 24 Inequality from Math Magazine 2009
Oct 24 Lagrange's identity, Proof
Oct 24 Fermat Points and Concurrent Euler Lines II
Oct 22 Fermat Points and Concurrent Euler Lines I
Oct 22 Some Properties of Napoleon's Configuration
Oct 20 Mixing maths and fiction for a higher purpose
Oct 19 Scheduling and Critical Path Algorithm
Oct 17 Problem 3, APMO 1989
Oct 15 Problem 4, APMO 1995
Oct 12 Ptolemy on Hinges
Oct 12 Jan Stevens' proof of E. W. Dijkstra's Generalization of the Pythagorean theorem
Oct 9 Traveling Salesman Problem
Oct 8 APMO 1991 Problem 1
Oct 5 Finding Hamilton Paths and Circuits
Oct 4 Method of Markers II
Oct 1 Problem A2, 69th Putnam Competition
Oct 1 Problem A1, 69th Putnam Competition
Sept 30 Rational Points On a Circle
Sept 29 A Sushi Morsel
Sept 29 Rhombus in a Cyclic Quadrilateral
Sept 29 Proof #82 of the Pythagorean theorem
Sept 27 Fleury's Algorithm and Euler's Paths and Cycles
Sept 24 Five Methods of Apportionment
Sept 20 Hunting Right Angles
Sept 16 An Identity in a Regular Heptagon
Sept 15 Fair Division: Method of Sealed Bids II
Sept 10 APMO 2003, Problem 2
Sept 6 Sum of Squares of Distances to Vertices
Sept 4 Distance between the Orthocenter and Circumcenter
Sept 3 APMO 1998, Problem 4
Sept 2 APMO 2004, Problem 2
Aug 29 Geometric Optimization from the Asian Pacific Mathematical Olympiad
Aug 29 Yet Another Puzzle with Hats
Aug 28 Banzhaf Power Index Calculator
Aug 28 Shapley-Shubik Power Index Calculator
Aug 17 Four Voting Methods
Aug 17 Simple Graph Practice
July 26 Cabart's Collinearity
July 26 Napoleon-Barlotti Theorem
July 23 Napoleon's Relatives
July 22 Three Dimensional Cross
July 21 Napoleon on Hinges
July 20 Cavalieri's Principle
July 19 Problem 1 from the IMO 2009
July 19 Problem 4 from the IMO 2009
July 14 Mechanical Proofs of the Pythagorean Theorem
July 14 Invariant Area Sweep Implies Pythagorean Theorem
July 9 Uncountability of the Reals - via a Game
July 6 Integer Iterations on a Circle III
July 5 Minumum Spanning Trees and Kruskal's Algorithm
July 2 Structure of Hyperreal Numbers
June 29 One Dimensional Ants
June 19 What Is Demagoguery?
June 17 Hyperintegers and Hyperreal Numbers
June 9 Models and Metamathematics
June 5 Fibonacci's Quickies
June 1 May the Product of Planes Be a Sphere?
May 31 Dollars in Pockets
May 31 One Trigonometric Formula and Its Consequences
May 29 Bimedians in a Regular Tetrahedron
May 29 Two Parallels in a Triangle and One More
May 28 Clifford Algebras
May 27 A better solution to a difficult sangaku problem
May 27 A Restored Sangaku
May 26 Probability of Divisibility
May 26 Product of Simple Fractions
May 26 IMO 2007, Problem 2, solution by Vo Duc Dien
May 25 Sum of Squares in Equilateral Triangle
May 21 Bisection of Yin and Yang
May 19 Counting Squares in a Square
May 15 A Review of Pythagoras' Revenge by Arturo Sangalli
May 15 A Line in a Square Grid
May 14 Two Color Coloring of the Plane
May 11 Two Sangaku with Equal Incircles
May 8 Formal Systems - an Example
May 5 GCD(M, N) × LCM(M, N) = M × N
May 4 What Is Fraction?
May 3 Fraction Comparison
Apr 29 Gödel's Incompleteness Theorem
Apr 29 Theories and Proofs
Apr 28 Morley's Theorem, Proof by R. Smyth
Apr 27 Napoleon's Theorem via Two Rotations
Apr 26 Morley's theorem, Proof by Nolan L Aljaddou
Apr 23 Möbius' Strip
Apr 11 Intuitive Probability
Apr 10 Dawson's Kayles
Apr 10 Dawson's Chess
Apr 3 On the Games of Hex and Y
Apr 3 Infinitesimals. Non-standard Analysis
Apr 2 Infinitude of Primes - A Topological Proof without Topology
Apr 1 A Triangle of Antreas Hatzipolakis
Mar 31 Six Concyclic Points II
Mar 30 Solutions to the Third Millennium Olympiad
Mar 29 Grebe: from Ladies' Diary to Carroll's Pillow
Mar 25 A Parallelogram in Triangle
Mar 24 Is Every Trapezoid Parallelogram?
Mar 23 On the Difference of Areas
Mar 21 Matrix Groups
Mar 18 Number 8 Is Interesting
Mar 14 Iterations on a Circle Through Three Points
Mar 14 Pigeonhole in Clubs
Mar 8 Angles in a Cube III
Mar 7 Squares in Circles
Mar 7 Circles with Tangent Diameters
Mar 3 Four Hinged Squares: using complex numbers
Feb 28 A Minesweeper Theorem
Feb 20 Proof 19 of irrationality of 2
Feb 17 Angles in a Cube I
Feb 17 Angles in a Cube II
Feb 12 Pascal: Necessary and Sufficient
Feb 6 Butterflies in Hyperbola
Feb 4 Problem 5 from IMO 2004
Feb 4 Morley's theorem, a proof by B. Stonebridge
Feb 2 Urquhart's theorem - From Leningrad Mathematical Olympiad
Jan 31 An Inequality for Grade 8
Jan 30 Proof 81 of the Pythagorean theorem
Jan 29 Morley's theorem, B. Bollobás' proof
Jan 27 Stereographic Projection
Jan 23 Problem 1 from IMO 2006
Jan 20 Irrationality of 2, Proof #14 and Proof #8''
Jan 18 Tangent Circles and an Isosceles Triangle II
Jan 17 Problem 4 from IMO 2007, Solution VII
Jan 16 Three Pyramids are Better Than Two
Jan 15 Orthocenter and Three Equal Circles
Jan 14 Equal Circles, Medial Triangle and Orthocenter
Jan 13 Cut the Cube
Jan 13 Cut the Cylinder
Jan 11 Cut the Cone
Jan 8 Between Major and Minor Circles
Jan 6 An Interesting Example of Angle Trisection by Paperfolding
Jan 5 Fundamental Theorem of Algebra: A Simple Complex Analysis Proof and An Advanced Calculus Proof
Jan 3 Irrationality of 2, Proof #17, Proof #18, Proof #19
Jan 2 Construction of Conics from Pascal's Theorem
Jan 1 Irrationality of 2, Proof #16

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