Algebra articles, problems, and puzzles.

What Is Arithmetic?
What Is Algebra?
Arithmetic: Articles and Problems

  1. 17 rooks on an 8×8 chessboard
  2. 1962 IMO, Problem 2: an inequality with a twist
  3. 1=2 via Continued Fractions
  4. 3-Colors Tower of Hanoi [Java]
  5. 3 glass puzzle [JavaScript]
  6. 3-Term Arithmetic Progression
  7. A 2-Variable Optimization From a China Competition
  8. A 4-variable Inequality from the RMM
  9. 4x4 coloring problem
  10. 6th European Mathematical Cup (2017), Junior Problem 4
  11. A 49th Degree Challenge
  12. A Case for Determinants
  13. A Case of Divergence
  14. A Clique of Acquaintances
  15. A Curious Property of Numbers 3 and 5
  16. A Cyclic But Not Symmetric Inequality in Four Variables
  17. A Cyclic Inequality by Seyran Ibrahimov
  18. A Cyclic Inequality from Math Phenomenon
  19. A Cyclic Inequality in Three Variables
  20. A Cyclic Inequality in Three Variables II
  21. A Cyclic Inequality in Three Variables III
  22. A Cyclic Inequality in Three Variables IV
  23. A Cyclic Inequality in Three Variables V
  24. A Cyclic Inequality in Three Variables VI
  25. A Cyclic Inequality in Three Variables VII
  26. A Cyclic Inequality in Three Variables VIII
  27. A Cyclic Inequality in Three Variables IX
  28. A Cyclic Inequality in Three Variables X
  29. A Cyclic Inequality in Three Variables XI
  30. A Cyclic Inequality in Three Variables XII
  31. A Cyclic Inequality in Three Variables XIII
  32. A Cyclic Inequality in Three Variables XIV
  33. A Cyclic Inequality in Three Variables XV
  34. A Cyclic Inequality in Three Variables XVI
  35. A Cyclic Inequality in Three Variables XVII
  36. A Cyclic Inequality in Three Variables XVIII
  37. A Cyclic Inequality in Three Variables XIX
  38. An Estimate for the Roots of Quadratic Equation
  39. An Exercise in Complex Numbers: Problem 4217 from Crux
  40. An Inequality with Constraint XX
  41. A Cyclic Inequality in Three Variables XX
  42. A Cyclic Inequality in Three Variables XXI
  43. A Cyclic Inequality in Three Variables XXII
  44. A Cyclic Inequality in Three Variables XXIII
  45. A Cyclic Inequality in Three Variables XXIV
  46. A Cyclic Inequality in Three Variables XXV
  47. A Cyclic Inequality in Three Variables XXVI
  48. A Cyclic Inequality in Three Variables And One More
  49. >A Cyclic Inequality In Three Variables by Sorin Radulescu
  50. A Cyclic Inequality in Three Variables by Uche E. Okeke
  51. A Cyclic Inequality from India In Three Variables And More
  52. A Cyclic Inequality in Three Variables with Constraint
  53. A Cyclic Inequality in Three or More Variables
  54. A Cyclic Inequality of Degree Four
  55. A Cyclic Inequality With Constraint in Two Triples of Variables
  56. A Cycling Inequality with Integrals
  57. A Cycling Inequality with Integrals II
  58. A Cyclic Inequality with Many Sums
  59. A Cyclic Inequality with Powers 2 through 7
  60. A Cyclic Inequality in Three Variables with a Variable Hierarchy
  61. A Cyclic Inequality on [-1,1]
  62. A Diophantine Equation - Problem from 2000 Belarus MO
  63. A Diophantine Equation with Square Roots - Problem from the 2008 British MO
  64. A DIY Proof of the Irrationality of sqrt(2)
  65. A Fancy Sum from the APMO 2000, Problem 1
  66. A Few Variants of a Popular Inequality And a Generalization
  67. A Formula for sin(3x)
  68. A Functional Equation from 1968 IMO
  69. A Functional Equation from the 2012 IMO
  70. A Generalization of an Inequality from a Romanian Olympiad
  71. A Limit of a Sequence
  72. A Limit of Another Sequence
  73. A Limit of a Series of Determinants
  74. A Limit with Fractions, Roots, Powers and Series
  75. A Limit With Sums, Roots, And Binomial Coefficients
  76. A Little of Algebra for an Inequality, A Little of Calculus for a Generalization
  77. A Little More of Algebra for an Inequality, A Little Less of Calculus for a Generalization
  78. A Long Cyclic Inequality of Degree 4
  79. A Low Bound for 1/2 * 3/4 * 5/6 * ... * (2n-1)/2n
  80. A Mathematical Rabbit out of an Algebraic Hat
  81. A Memorable Fact
  82. A Middle School Problem from a Moscow Olympiad
  83. A Moscow Olympiad Question with Two Inequalities
  84. A New Proof That the Rationals Are Countable
  85. A Not Quite Cyclic Inequality
  86. A Not Quite Cyclic Inequality from Tibet
  87. A Not Symmetric Inequality [JavaScript]
  88. A Not So Simple Inequality in Three Variables
  89. A One-Line Proof of the Infinitude of Primes
  90. A Partly Cyclic Inequality in Four Variables
  91. A Problem for the 2015 New Year's Eve
  92. A Problem From a Mongolian Olympiad for Grade 11
  93. A Problem from Croatian TST
  94. A Problem form the Short List of the 2018 JBMO
  95. A Problem from the Danubius Contest 2016
  96. A Problem from the Danubius-XI Contest
  97. A Problem From the Romanian Mathematical Competitions (2016)
  98. A Problem in Complex Numbers Sets 3 Aside
  99. A Problem in Division of Polynomials
  100. A Problem with a Magical Solution from Secrets in Inequalities
  101. A Proof by Game for a Sum of a Convergent Series
  102. A Property of Number 4
  103. A Property of Product of Special Matrices, Probably Folklore
  104. A Property of the fusc() Function
  105. A Refinement of Turkevich's Inequality
  106. A Representation of Rational Numbers
  107. A Quartic Equation
  108. A Series with k-Permutations
  109. A Simple Inequality with Many Variables
  110. A Simple Cyclic Inequality in Three Variables
  111. A Simple Inequality in Three Variables
  112. A simple integral
  113. A simple integral, III
  114. A Simple Integral of a Peculiar Function
  115. A Simplified Version of Leo Giugiuc's Inequality from the AMM
  116. A Sum by Dorin Marghidanu
  117. A Sum of a Double Series
  118. A System of Equations Begging for Generalization
  119. A System of Equations in Determinants
  120. A System of Two Equations Replete with Squares
  121. A Telescoping Series
  122. A Tricky Integral Inequality
  123. A Trigonometric Inequality from the RMM
  124. >A Trigonometric Observation in Right Triangle
  125. A Triple Integral Inequality
  126. A True Algebraic-Geometric Inequality
  127. A Warmup Inequality from Vasile Cirtoaje
  128. ab + bc + ca ≤ aa + bb + cc
  129. About numbers
  130. Absolute Value
  131. Absolute Value and 1998 integers
  132. Achieve the Equilibrium [Flash]
  133. Addition
  134. Addition and Subtraction Formulas for Sine and Cosine III
  135. Addition and Subtraction Formulas for Sine and Cosine IV
  136. Advancing a Millenium Problem [JavaScript]
  137. Affirmative Action Problem [Java]
  138. Algebraic-Geometric Inequality
  139. Algebraic Structure of Complex Numbers
  140. All Integers Are Equal to 1
  141. All Integers Are Even
  142. All Powers of 2 Are Equal to 1
  143. All Powers of x are Constant
  144. Almost every integer has the digit 3 in it
  145. Almost Integers - Gaussian Integers
  146. Amazing Mix of Triangular Numbers and Golden Ratio
  147. Ambassadors at a Round Table [Java]
  148. An Acyclic Inequality in Three Variables
  149. An Algebraic Lemma with Geometric Consequences [JavaScript]
  150. An Application of Quadratic Formula
  151. An Arctan Identity and its Consequence [JavaScript, GeoGebra]
  152. An Easy Cyclic Inequality And a Remark
  153. An Easy Inequality with Three Integrals
  154. An Elementary Inequality by Non-elementary Means
  155. An Elementary Proof for Euler's Series
  156. An Equation in Determinants
  157. An Equation in Factorials
  158. An Equation in Matrices
  159. An Equation in Radicals
  160. An Equation in Reciprocals
  161. An Equation in RxR from Romania
  162. An Equation in Squares [JavaScript]
  163. An Equation Involving Four Collinear Points
  164. An Exercise without Calculating Aids
  165. An Identity between the Roots of a Cubic Polynomial - Problem from the 2007 Irish MO
  166. An Identity From the 2010 China Mathematical Competition
  167. An Identity Involving the Integer Part - Problem from the 1981 Canadian MO
  168. An Incidental Sum of 24
  169. An Increasing Sequence from 2014 IMO
  170. An Inequality and Its Modifications
  171. An Inequality between AM, QM and GM
  172. An Inequality by Uncommon Induction
  173. An Inequality for Grade 8
  174. An Inequality from a Mongolian Exam
  175. An Inequality from the 1967 IMO Shortlist
  176. An inequality from 1971 Canadian Mathematical Olympiad
  177. An Inequality from Marocco [JavaScript]
  178. An Inequality from Tibet
  179. An inequality in 2+2 variables from SSMA magazine
  180. Inequality in Convex Quadrilateral
  181. An Inequality in Determinants
  182. An Inequality in Four Weighted Variables
  183. An Inequality in Fractions with Absolute Values
  184. An Inequality in Integers [JavaScript]
  185. An Inequality in Integers II
  186. An Inequality in Parallelogram of Unit Area
  187. An Inequality in Reciprocals
  188. An Inequality in Reciprocals II An Inequality in Reciprocals III
  189. An Inequality in Three (Or Is It Two) Variables
  190. An Inequality in Triangle and In General
  191. An Inequality In Triangle and Without
  192. An Inequality In Triangle and Without II
  193. An Inequality in Two Or More Variables
  194. An Inequality in Two Or More Variables II
  195. An Inequality Involving Arithmetic And Geometric Means
  196. An Inequality Solved by Changing Appearances
  197. An Inequality with Angles and Integers
  198. An Inequality with Arbitrary Roots
  199. An Inequality with Areas, Norms, and Complex Numbers
    200. An Inequality with Central Binomials
  200. An Inequality with Complex Numbers of Unit Length
  201. An Inequality with Complex Numbers of Unit Length II
  202. An Inequality with Cubic Roots
  203. An Inequality with Cyclic Sums And Products
  204. An Inequality with Cyclic Sums on Both Sides
  205. An Inequality with Cyclic Sums on Both Sides II
  206. An Inequality with Cyclic Sums on Both Sides III
  207. An Inequality with Exponents
  208. An Inequality with Five Variables, Only Three Cyclic
  209. An Inequality with Fractions
  210. An Inequality with Integrals
  211. An Inequality with Integrals and Radicals
  212. An Inequality with Just Two Variable And an Integer
  213. An Inequality with Sines But Not in a Triangle
  214. An Inequality with One Tangent and Six Sines
  215. An Inequality with Powers And Logarithm
  216. An Inequality With Six Variables and Constraints
  217. An Inequality Where One Term Is More Equal Than Others
  218. An Inequality with a Parameter and a Constraint
  219. An Inequality with Absolute Values
  220. An Inequality with an Infinite Series
  221. An Inequality with Constraint
  222. An Inequality with Constraints II
  223. An Inequality with Constraint III
  224. An Inequality with Constraint IV
  225. An Inequality with Constraint V
  226. An Inequality with Constraint VI
  227. An Inequality with Constraint VII
  228. An Inequality with Constraint VIII [JavaScript]
  229. An Inequality with Constraint IX [JavaScript]
  230. An Inequality with Constraint X [JavaScript]
  231. An Inequality with Constraint XI [JavaScript]
  232. An Inequality with Constraint XII
  233. An Inequality with Constraint XIII
  234. An Inequality with Constraint XIV
  235. Inequalities with Constraint XV and XVI
  236. An Inequality with Constraint XVII
  237. An Inequality with Constraint XVIII
  238. An Inequality with Constraint XIX
  239. An Inequality with Constraint in Four Variables
  240. An Inequality with Constraint in Four Variables II
  241. An Inequality with Constraint in Four Variables III
  242. An Inequality with Constraint in Four Variables IV
  243. An Inequality with Constraint in Four Variables V
  244. An Inequality with Constraint in Four Variables VI
  245. An Inequality with Cot, Cos, and Sin
  246. An Inequality with Cycling Sums
  247. An Inequality with Determinants [JavaScript]
  248. An Inequality with Determinants II
  249. An Inequality with Determinants III
  250. An Inequality with Determinants IV
  251. An Inequality with Determinants V
  252. An Inequality with Determinants VI
  253. An Inequality with Determinants VII
  254. An Inequality with Exponents [JavaScript]
  255. An Inequality with a Generic Proof [JavaScript]
  256. An Inequality with Nested Radicals
  257. An Inequality via Young's Theorem
  258. An Inequality with Just Two Variable
  259. An Inequality with Just Two Variable II
  260. An Inequality with Just Two Variable III
  261. An Inequality with Just Two Variables IV
  262. An Inequality with Just Two Variables V
  263. An Inequality with Just Two Variables VI
  264. An Inequality with Just Two Variable VII
  265. An Inequality with Just Two Variable VIII
  266. An Inequality with Permutations, I [JavaScript]
  267. An Inequality with Permutations, II [JavaScript]
  268. An Inequality with Two Cyclic Sums
  269. An Inequality with Two Pairs of Triplets An Inequality with Two Triples of Variables
  270. An Inequality with Two Triples of Variables II
  271. Inequality with Two Variables? Think Again
  272. An Inequality with Two Variables from Awesome Math
  273. An Infinite Product from Recursion
  274. An Integer Root of a Polynomial with Integer Coefficients
  275. An Integral Estimate
  276. An Integral Identity with Two Functions
  277. An Integral from the RMM
  278. An Integral Inequality from the RMM
  279. An Old Inequality
  280. An Unsolvable Riccati Equation
  281. An Unusual Quadratic Equation
  282. Another Face and Proof of a Trigonometric Identity
  283. Another Inequality with Logarithms, But Not Really
  284. Another Integral Inequality from the RMM
  285. Another Problem from the 2016 Danubius Contest
  286. Another Property of Number 4
  287. Another simple integral
  288. An Unusual Problem by Leo Giugiuc
  289. Any Integer with Three 2s
  290. Application of Cauchy-Schwarz Inequality
  291. Applications of Schweitzer's Inequality
  292. Approximation Of Roots
  293. Area of a Circle by Rabbi Abraham bar Hiyya Hanasi [Java]
  294. Areas on the Graphs of Power Functions
  295. Arithmetic-Geometric Means Inequality
  296. Arithmetic of Pie Sharing
  297. Ascending Bases and Exponents in Pascal's Triangle
  298. Assigning Numbers to Points in the Plane
  299. Associativity from 1977 IMO
  300. Averages, Arithmetic and Harmonic Means [Java]
  301. Averages in a sequence
  302. Ballot Lemma [Java]
  303. Banzhaf Power Index Calculator [Java]
  304. Barcode Encoding
  305. Barcode Magic [Java]
  306. Base Converter [JavaScript]
  307. Bergström's inequality
  308. Birth of an Inequality
  309. Bayes' Theorem
  310. Beatty Sequences
  311. Beauty and the Beast - in Trigonometry
  312. Bertrand's Postulate
  313. Bicubal Domino [JavaScript]
  314. Bilateral Diagrams [Java]
  315. Binet's Formula via Generating Functions
  316. Binet's Formula with Cosines
  317. Binomial Distribution [Java]
  318. Binomial Theorem
  319. Bisector of an imaginary angle may be real
  320. Brahmagupta-Fibonacci Identity [JavaScript]
  321. Byzantine Basketball
  322. Calculation of the Digits of pi by the Spigot Algorithm [Java]
  323. Calculus Proof of the Pythagorean Theorem
  324. Candido's Identity
  325. Cantor-Bernstein-Schroeder theorem
  326. Cantor's First Uncountability Proof
  327. Cardinal Numbers
  328. Cartesian Coordinate System [Java]
  329. Cassini's Identity
  330. Catalan Numbers in Pascal's Triangle
  331. Cavalieri's Principle [Java]
  332. Central and Inscribed Angles in Complex Numbers
  333. Chebyshev Inequality
  334. Chebyshev Holds a Key
  335. Check for Negative Roots
  336. Chess tournament with 1.5 Points Winners
  337. Chinese Remainder Theorem
  338. Clifford Algebras
  339. Clubs in a Vector Space
  340. Collatz Conjecture [Java]
  341. Coloring a Graph [Java]
  342. Coloring Squares, Adding up Numbers
  343. Combinatorial Proofs
  344. Combo Playground: Calculating the Number of Paths on a Square Grid
  345. Committee Chairs
  346. Comparing complex numbers
  347. Completing a Square and Quadratic Formula
  348. Completing the Square Where It Matters
  349. Complex Numbers: A Dynamic Tool [Java]
  350. Complex number to a complex power may be real
  351. Complicated Constraint - Simple Inequality
  352. Composition of Functions, an Exercise Constrained Inequality with Reciprocals
  353. Constrained Intermarriages [JavaScript]
  354. Constructible Numbers
  355. Construction of Pascal's Triangle [Java]
  356. Constructive Existence of the de Bruijn Cycles
  357. Continued fractions
  358. cos/sin inequality
  359. cos(π/7)-cos(2π/7)+cos(3π/7) = 1/2
  360. Cospherical Points
  361. Countability of Rational Numbers
  362. Countability Principle
  363. Counting Chips On a Circle [Java]
  364. Counting Fat Sets
  365. Counting Squares in a Square [Java]
  366. Counting Triangles [Java]
  367. Counting Triangles II [Java]
  368. Covering a Chessboard with a Hole with L-Trominoes [Java]
  369. Covering A Chessboard With Domino
  370. Cubes Constrained
  371. Cubes in Pascal's Triangle
  372. Cubic Equation for the Sides of a Triangle
  373. Cubic Formula [JavaScript]
  374. Cubics and Bézout's Theorem
  375. Cubic Optimization with Linear Constraints
  376. Cubic Optimization with Partly Linear Constraints
  377. Curious Identities In Pythagorean Triangles
  378. Curious Identities Involving Integer Products

    Cute Exercise by Dorin Marghidanu

  379. Cyclic Inequality in Four Variables
  380. Cyclic Inequality in Four Variables By D. Sitaru
  381. Cyclic Inequality in Three Variables by Marian Cucoanes
  382. Cyclic Inequality In Three Variables from the 2018 Romanian Olympiad, Grade 9
  383. Cyclic Inequality In Three Variables From Vietnam by Rearrangement
  384. Cyclic Inequality with Arctangents
  385. Cyclic Inequality with Logarithms
  386. Cyclic Inequality with Square Roots
  387. Cyclic Inequality with Square Roots And Absolute Values
  388. Dan Sitaru's Amazing, Never Ending Inequality
  389. Dan Sitaru's Cyclic Inequality in Four Variables
  390. Dan Sitaru's Cyclic Inequality In One Variable
  391. Dan Sitaru's Cyclic Inequality In Many Variables
  392. Dan Sitaru's Cyclic Inequality In Three Variables
  393. Dan Sitaru's Cyclic Inequality in Three Variables II
  394. Dan Sitaru's Cyclic Inequality in Three Variables III
  395. Dan Sitaru's Cyclic Inequality in Three Variables IV
  396. Dan Sitaru's Cyclic Inequality in Three Variables V
  397. Dan Sitaru's Cyclic Inequality in Three Variables VI
  398. Dan Sitaru's Cyclic Inequality in Three Variables VII
  399. Dan Sitaru's Cyclic Inequality in Three Variables VIII
  400. Cyclic Inequality In Three Variables From Kvant
  401. Dan Sitaru's Cyclic Inequality In Three Variables with Constraints
  402. Dan Sitaru's Cyclic Inequality In Three Variables with Constraints IV
  403. Dan Sitaru's Cyclic Inequality In Three Variables with Constraints V
  404. Dan Sitaru's Exercise with Pi and Ln
  405. Dan Sitaru's Inequality: From Three Variables to Many in Two Ways
  406. Dan Sitaru's Cyclic Inequality In Three Variables with Constraints II
  407. Dan Sitaru's Cyclic Inequality In Three Variables with Constraints III
  408. Dan Sitaru's Cyclic Inequality in Three Variables IX
  409. Dan Sitaru's Inequality by Induction
  410. Dan Sitaru's Cyclic Inequality with a Constraint and Cube Roots
  411. Dan Sitaru's Cyclic Inequality with a Constraint and Cube Roots II
  412. Dan Sitaru's Inequality with a Double Integral
  413. Dan Sitaru's Inequality with Roots and Powers
  414. Dan Sitaru's Inequality with Tangents
  415. Dan Sitaru's Inequality with Three Related Integrals and Derivatives
  416. Dan Sitaru's Integral Inequality with Powers of a Function
  417. Dan Sitaru's Sum of a Series
  418. Daniel Dan's Optimization in Three Variables
  419. Darij Grinberg's Inequality In Three Variables
  420. Deceptive Appearances
  421. Decimal Sums of Successive Integers
  422. Derivatives without Limits
  423. Descartes' Rule of Signs
  424. Determinant and Divisibility
  425. Determinant on a Circle
  426. Determinants in Pascal's Triangle
  427. Diagonal Argument
  428. Diophantine Equations
  429. Distance between the Orthocenter and Circumcenter
  430. Distance Between Strings [Java]
  431. Distance From a Point to a Straight Line [Java]
  432. Distance Inequality
  433. Distances to Three Points on a Circle
  434. Distinct Multisets with the Same Pairwise Sum
  435. Divergence of {cos(n)} [JavaScript]
  436. Divergence of the Harmonic Series (Details)
  437. Divide And Conquer in Cyclic Sums
  438. Dividing Loot Fairly
  439. Divisibility and Modulo Arithmetic at IMO 2007
  440. Divisibility by Powers of 2
  441. Dollars in Pockets
  442. Doodling on April 1st
  443. Dorin Marghidanu's Believe It Or Not
  444. Dorin Marghidanu's Calculus Lemma
  445. Dorin Marghidanu's Cyclic Inequality in Three Variables
  446. Dorin Marghidanu's Cyclic Inequality in Three Variables II
  447. Dorin Marghidanu's Cyclic Inequality in Three Variables III
  448. Dorin Marghidanu's Cyclic Inequality with Constraint
  449. Dorin Marghidanu's Inequality in Complex Plane
  450. Dorin Marghidanu's Functional Equation
  451. Dorin Marghidanu's Inequality in Integer Variables
  452. Dorin Marghidanu's Inequality in Many Variables
  453. Dorin Marghidanu's Inequality in Many Variables Plus Two More
  454. Dorin Marghidanu's Inequality with Constraint
  455. Dorin Marghidanu's Inequality with Generalization
  456. Dorin Marghidanu's Inequality with Powers and Reciprocals
  457. Dorin Marghidanu's Inequality with Radicals
  458. Dorin Marghidanu's Light Elegance in Four Variables
  459. Dorin Marghidanu's Permuted Inequality
  460. Dorin Marghidanu's Spanish Problem Dorin Marghidanu's Sums and Products
  461. Dorin Marghidanu's Tribute to Descartes
  462. Dorin Marghidanu's Two-Sided Inequality
  463. Dot Patterns and Sierpinski Gasket [Java]
  464. Dots and fractions [Java]
  465. Double and Half Angle Formulas
  466. Double Sums by Dorin Marghidanu
  467. Ducci Sequences [Java]
  468. e in the Pascal Triangle
  469. EAN-13 Encoding [Java]
  470. Eigenvectors by Inspection
  471. Elves and Gnomes [JavaScript]
  472. Entry 1.414... in Ramanujan's Notebooks
  473. Equation in Permutations
  474. Equation in Radicals as a System of Equations
  475. Equations of the Staight Line [Java]
  476. Equivalence Relations
  477. Escape of the Clones
  478. Euclid's Algorithm
  479. Euclid's Algorithm: An Interactive Illustration [Java]
  480. Euler Cycles in Digraph
  481. Euler's formula for eiθ
  482. Euler's Function and Congruence Theorem
  483. Evolution of Algebraic Symbolism
  484. Exercise with Square Spiral [GeoGebra]
  485. Existence of the de Bruijn Cycles via Graphs
  486. Exponential Inequalities for Means
  487. Extension of Euclid's Algorithm
  488. Extrema of x^3+y^3+z^3-xyz on the unit sphere
  489. Factorial Products
  490. Factorials and division
  491. Fair Division: Method of Sealed Bids II [Java]
  492. Falsity implies anything
  493. Farey Series
  494. Fermat's Like Equation
  495. Fermat's Little Theorem
  496. Fermat's Only Published Proof
  497. Fibonacci Idendtities with Matrices
  498. Fibonacci's Quickies
  499. Fibonacci Tilings
  500. Filling a Grid with Good Neighbors [Java]
  501. Filling an Array with 0s and 1s - and Counting [Java]
  502. Filling Pool with Fluids
  503. Find Minimum without Calculus
  504. Find the Maximum and Minimum of a Function
  505. Finding Hamilton Paths and Circuits [Java]
  506. Finite Sums of Terms 2^(n-i) i²
  507. First 1008 Digits
  508. First Geometric Interpretation of Complex Numbers [Java]
  509. Five Methods of Apportionment [Java]
  510. Five Lattice Points [Java]
  511. Five Squares in Complex Numbers [GeoGebra]
  512. Fixed Point of a Family of Parabolas
  513. Fleury's Algorithm and Euler's Paths and Cycles [Java]
  514. Flipping Items Simultaneously [Java]
  515. Flipping Items Simultaneously II [Java]
  516. Flipping Items Simultaneously III [Java]
  517. Flipping pancakes [Java]
  518. Floor Function
  519. Formal Systems - an Example
  520. Formula for Primes
  521. Four Hinged Squares: using complex numbers
  522. Four Integrals in One Inequality
  523. Four Numbers, Six Differences, GCD of the Products
  524. Four Pegs That Form a Square
  525. Four Voting Methods [Java]
  526. From The Sum of Angles To The Sum of Sines
  527. Function
  528. Function in the Plane That Vanishes
  529. Functional Inequality from Vietnam
  530. Fundamental Theorem of Algebra
  531. Futurama Theorem and Puzzle [Java]
  532. Gasoline Stations on a Circular Trek
  533. Gauss and Euler Integrals
  534. Gauss' Lemma
  535. Gauss' theorem on constructibility of regular polygons
  536. GCD of Fibonacci Numbers
  537. GCD(M, N) × LCM(M, N) = M × N [Java]
  538. Generalization That Solves the Problem
  539. Generating Functions
  540. Geometric Construction of Roots of Quadratic Equation [Java]
  541. Getting a Scout out of Desert [Java]
  542. Getting Your Rightful Share Back [JavaScript]
  543. Gheorghe Stoica's Problem from Gazeta Matematica Gireaux's Theorem
  544. Gödel's Incompleteness Theorem
  545. Golden Ratio is Irrational
  546. Graph and Roots of a Third Degree Polynomial [Java]
  547. Graph and Roots of Quadratic Polynomial [Java]
  548. Graph of a Polynomial [Java]
  549. Graph of a Polynomial Defined by Its Roots [Java]
  550. Graph with Nodes of Even Degree
  551. Graph without 3-Cycles
  552. Graphing Equations Is Useful
  553. Graphing Equations Is Useful, II [Java]
  554. Graphing Equations Is Useful, III
  555. Graphing Equations Is Useful, IV
  556. Graphing Equations Is Useful, V
  557. Greatest Difference in Arithmetic Progression
  558. Group multiplication of permutations [Java]
  559. 1/2 = 1
  560. Hadamard's Determinant Inequalities and Applications I
  561. Hadamard's Determinant Inequalities and Applications II
  562. Harmonic Serires And Its Parts
  563. 2006 Hellenic Mathematical Olympiad, Problem 4 [JavaScript]
  564. Hlawka's Inequality
  565. Horner's Method [Java]
  566. How Jost Burgi Computed the Sines of All Integer Angles in 1586
  567. How to Ask an Embarrassing Question
  568. How to define a permutation? [Java]
  569. How to write an equation of the union of two sets
  570. However You Solve It ... A Wonderful Equation
  571. Hung Viet's Inequality
  572. Hung Viet's Inequality II
  573. Hung Viet's Inequality III
  574. Hung Viet's Inequality IV
  575. Hyperintegers and Hyperreal Numbers
  576. Identities with Triangular Numbers
  577. Imad Zak's Cyclic Inequality in Three Variables
  578. Imad Zak's Cyclic Inequality in Three Variables II
  579. Implementation of Base Conversion
  580. Importance of the Absolute Value
  581. Improving an Inequality [JavaScript]
  582. Improving on an Escalator [JavaScript]
  583. In Calculus too 1 = 0
  584. Inclusion-Exclusion Principle
  585. Inclusion-Exclusion Principle: an Example
  586. Inequalities and Quadratic Forms
  587. An Inequality for Mixed Means
  588. An Inequality from RMM with a Generic 5
  589. An Inequality from RMM with Powers of 2
  590. Inequality 101 from the Cyclic Inequalities Marathon
  591. Inequality 1/2·3/4·5/6· ... ·99/100
  592. Inequality (1 + 1-3)(1 + 2-3)(1 + 2-3)...(1 + n-3)
  593. Inequality 1 + 2-2 + 3-2 + 4-2 + ... + n-2
  594. Inequality by Calculus
  595. Inequality for Integer Sequences
  596. Inequality for Integer Sequences II
  597. Inequality for Mixed Means
  598. An Inequality from Gazeta Matematica, March 2016
  599. An Inequality from Gazeta Matematica, March 2016 II
  600. An Inequality from Gazeta Matematica, March 2016 III
  601. An Inequality from Gazeta Matematica, March 2016 IV
  602. Inequalities with Double And Triple Integrals
  603. Inequality from Math Magazine 2009
  604. Inequality from Math Phenomenon
  605. Inequality in Acute Triangle
  606. Inequality of a Series of Square Roots
  607. Inequality with Constraint from Dan Sitaru's Math Phenomenon
  608. Inequality with Csc And Sin
  609. An Inequality with Exponents [JavaScript]
  610. An Inequality with Finite Sums
  611. An Inequality with Integrals and Rearrangement
  612. Inequality with Logarithms
  613. Inequality with Powers And Radicals
  614. Inequality with Three Linear Constraints
  615. Inequality with Three Numbers, Not All Zero
  616. Inequality with Two Minima
  617. Infinite Discent for x4 + y4 = z4
  618. Infinitesimals. Non-standard Analysis
  619. Infinitude of Primes
  620. Infinity As a Limit
  621. Inflection Points of Fourth Degree Polynomials [Java]
  622. Inheriting Inequality
  623. An innovative recurrence
  624. Integer Iterations on a Circle [Java]
  625. Candy Game (Change Discharged) [Java]
  626. Integer Iterations on a Circle III [Java]
  627. Integer roots of integers are irrational
  628. Integer Triangle That Sums to Cube
  629. Integers and Rectangles [Java]
  630. Integers and Rectangles: a Proof by Induction [Java]
  631. Integers and Rectangles: Two Simple Proofs [Java]
  632. Integers With Digits 1 and 2 and Residues Modulo Powers of 2
  633. Integral in Normal Distribution
  634. Integral Is Area
  635. Integrals of a Function And Its Inverse
  636. Interest Calculations [Java]
  637. Integral of a Piece-wise Function
  638. Irrationality of k-th roots
  639. Irrationality of sqrt(2) via a Difference Equation
  640. Is GLOBALHELLFRY a Prime? [JavaScript]
  641. Is the Triangle Inequality Necessary?
  642. Is There a Limit?
  643. ISBN Encoding [Java]
  644. Irrational number to an irrational power may be rational
  645. Is 0.999... = 1?
  646. It's All About Powers of 10
  647. Iterations on Monotone Functions
  648. Jensen's Inequality [JavaScript]
  649. Ji Chen's Inequality
  650. Joachimsthal's Notations
  651. Jumping Isn't Everything [Java]
  652. Kaprekar's Iterations and Numbers [Java]
  653. Kulikowski's Theorem
  654. Kunihiko Chikaya's Inequality
  655. Kunihiko Chikaya's Inequality with a Constraint
  656. Kunihiko Chikaya's Inequality with Parameter
  657. Labeling Subsets
  658. Lagrange's identity, Proof
  659. Lagrange interpolation
  660. Lamé's Theorem - First Application of Fibonacci Numbers
  661. Langford and Skolem Sequences [Java]
  662. Latin Squares [Java]
  663. Le Khanh Sy's Problem
  664. Leech Trees and Taylor's Criterion
  665. Legendre's Formula
  666. Legendre's Theorem - The Prime Factorization of Factorials
  667. Leibniz and Pascal Triangles [Java]
  668. Leo Giugiuc and Vasile Cirtoaje's Cyclic Inequality
  669. Leo Giugiuc's Cyclic Inequality in Square Roots
  670. Leo Giugiuc's Cyclic Inequality in Three Variables
  671. Leo Giugiuc's Cyclic Quickie in Four Variables
  672. Leo Giugiuc's Cyclic Inequality with a Constraint
  673. Leo Giugiuc's Exercise
  674. Leo Giugiuc's Inequality with Constraint
  675. Leo Giugiuc's Optimization with Constraint
  676. Leo Giugiuc's Trigonometric Lemma
  677. Less than, Equal to, Greater Than Symbols
  678. Lewis Carroll's Game of Logic [Java]
  679. Light Bulbs in a Circle [Java]
  680. Lights Out [Java]
  681. Limit of a Recursive Sequence
  682. Linear Algebra Tools for Proving Inequalities
  683. Linear Algebra Tools for Proving Inequalities: Cauchy-Binet Formula
  684. Linear Function with Coefficients in Arithmetic Progression [GeoGebra]
  685. Linear functions
  686. Linear Programming
  687. Linear System with Parameter
  688. Listing All Combinations [Java]
  689. Listing all permutations [Java]
  690. Listing All Permutations: Johnson-Trotter Method [Java]
  691. Logistic Model applet [Java]
  692. Long Huynh Huu's Inequality and Solution
  693. Long Runs of Composite Numbers
  694. Long Up Short Down
  695. Looking your best
  696. Loop or Halt [Java]
  697. Lorian Saceanu's Cyclic Inequalities with Three Variables
  698. Lorian Saceanu's Inequality with Many Variables
  699. Lucas' Theorem
  700. Lucas' Theorem II
  701. Lucky Numbers [Java]
  702. Marian Dinca's Refinement of Nesbitt's Inequality
  703. Marriage Theorem
  704. Marriage Problem, simulation [Java]
  705. Math Lotto
  706. Mathematical Induction
  707. Mathematical Proof
  708. Mathematicians Doze Off
  709. Matrices and Determinants as Optimization Tools: an Example
  710. Matrix Groups
  711. Maximum Volume of a Cut Off Box [Java]
  712. Means [Java]
  713. Mediant Fractions
  714. Method of Markers II [Java]
  715. Michael Rozenberg's Inequality in Three Variables with Constraints
  716. Michael Rozenberg's Inequality in Two Variables
  717. Minesweeper Theorem
  718. Mini Lights Out [Java]
  719. Minimax Principle [Java]
  720. Minimax Theorem [Java]
  721. Minimum of a Cyclic Sum with Logarithms
  722. Minimum of Cotangents from Saint Petersburg
  723. Minumum Spanning Trees and Kruskal's Algorithm [Java]
  724. Minimum under Two Constraints
  725. Minus One But What a Difference
  726. Modular Arithmetic [Java]
  727. Monotone Convergence Theorem
  728. Monotone Number Sequences [Java]
  729. Monthly Problem 11199
  730. Much from Little
  731. Muirhead's Inequality
  732. Multiplication
  733. Multiplication of Points on a Circle [JavaScript, GeoGebra]
  734. Multiplication of Points on an Ellipse [JavaScript, GeoGebra]
  735. Napoleon's Relatives [Java]
  736. Negative on the left, positive on the right: how come?
  737. Nested Radicals
  738. Nested Subsets
  739. New Proof of Euclid's Theorem
  740. Newton's Method [Java]
  741. Newton's and Maclaurin's Inequalities [JavaScript]
  742. Hung Nguyen Viet's Inequality with a Constraint
  743. Nine Squares [Java]
  744. No Flipping without End [Java]
  745. NonSquare Matrix as a Tool for Proving an Inequality
  746. Number 8 Is Interesting
  747. Number Comparison - from the 1969 Canadian MO
  748. Number sequences and Pigeonhole [Java]
  749. Number System With Base 36
  750. Modern Vietnamese Classic
  751. On Dedekind Cuts
  752. On the Games of Hex and Y
  753. On the Intersection of kx and |sin(x)| [JavaScript]
  754. On the Intersection of 1+x and e^x and Trigonometric Consequences [JavaScript]
  755. One Dimensional Ants
  756. One Inequality - Two Domains
  757. One Trigonometric Formula and Its Consequences
  758. Optimization in Four Variables with Two Constraints
  759. Optimization with Many Variables
  760. Order. Well-ordered sets.
  761. Order and Chaos in Multiple Pendulums
  762. Ordinal Numbers
  763. Orthocenter in Complex Plane
  764. Outline Mathematics
  765. Problem 1 From the 2016 Pan-African Math Olympiad
  766. Problem 11867 from the American Mathematical Monthly
  767. Problem 2, the 36th IMO (1995)
  768. Problem 2 from the 2017 IMO
  769. Problem 3824 from Crux Mathematicorum
  770. Problem 3980 from Crux Mathematicorum
  771. Problem 4002 from Crux Mathematicorum
  772. Problem 4010 from Crux Mathematicorum
  773. Problem 4020 from Crux Mathematicorum
  774. Problem 4033 from Crux Mathematicorum
  775. Problem 4117 from Crux Mathematicorum
  776. Problem 4142 From Crux Mathematicorum
  777. Problem 4165 from Crux Mathematicorum
  778. Problem 4186 from Crux Mathematicorum
  779. Problem 6 from Dan Sitaru's Algebraic Phenomenon
  780. Problem 790 from Pentagon: an Inequality in Two Variables
  781. Problem From the 2016 IMO Shortlist
  782. Problem M317 from Crux Mathematicorum
  783. Proofs of Schweitzer's inequality
  784. Prove 2[sqrt(n) - sqrt(n-1)] > 1/sqrt(n)
  785. Sam Walters' Four Questions
  786. Same Integral, Three Intervals
  787. Samuel G. Walters' Congruence
  788. Simple Nameless Inequality
  789. Small Change Makes Big Difference
  790. Smallest multiple of 9 with no odd digits [Java]
  791. Snake Permutations And Their Number
  792. Solving a Peculiar Third Degree Equation
  793. The Basics of Infinite Descent
  794. The Joy of Homogeneity
  795. The Lucky Find [Java]
  796. The Mean Property of the Mean
  797. The Number of Judges and the Number of Votes [JavaScript]
  798. The power of substitution: solving an equation in a right triangle
  799. The power of substitution II: proving an inequality with three variables
  800. The power of substitution III: proving an inequality with two variables
  801. The Very First Functional Equation at IMO
  802. The Very Last, for 2014, proof of the Irrationality of sqrt(2)
  803. Three Colors on a Chessboard
  804. Three digit twister [Java]
  805. Who Has Beard? [Java]
  806. Outline Mathematics: Diophantine Equation I [JavaScript]
  807. p-adic Expansions
  808. p-adic Numbers
  809. Pairing Monotone and Convex Functions
  810. Parabola and Abutting Equilateral Triangles
  811. Parabolic Sieve of Prime Numbers
  812. Parity counting [Java]
  813. Parrondo Paradox Via Simpson Paradox [Java]
  814. Partial But General Case Of Fermat's Last Theorem
  815. Party Acquaintances [Java]
  816. Patterns in Pascal's Triangle
  817. Peano axioms
  818. Pennies in Boxes [Java]
  819. Percent
  820. Permutations
  821. Perrin Sequence
  822. Pi in Pascal's Triangle
  823. Pi in Pascal's Triangle via Triangular Numbers
  824. pi^e vs e^pi [JavaScript]
  825. Pigeonhole Principle
  826. Pinocchio as Epimenides
  827. Place Value [Java]
  828. Powers and Fractions Inequality
  829. Presence of the Antipodes on a Circle
  830. Prime Sums in Pairs
  831. Probability of Divisibility
  832. Problem 1 from the IMO 2009
  833. Problem 11804 from the AMM
  834. Problem A1, 69th Putnam Competition
  835. Problem A2, 69th Putnam Competition
  836. Problem of Divisibility by 5n
  837. Product of Diagonals in Regular N-gon
  838. Product Of Four Consecutive Integers
  839. Product of Integers that Add Up to 2018
  840. Product of Simple Fractions [Java]
  841. Product of permutations [Java]
  842. Proizvolov's Identity [Java]
  843. Proofs Without Words [Java]
  844. Property of an
  845. Property of Quadratic Polynomials
  846. Property of the Powers of 2 [Java]
  847. Puzzlist vs. Mathematician: A Practical Arithmetic Problem
  848. Pythagorean Triples [Java]
  849. Quadratic Function for Solving Inequalities
  850. Quadratic Inequalities on [-1,1]
  851. An Inequality Where One Term Is More Equal Than Others
  852. Quasigroups and block designs from triangular grid [Java]
  853. Rabbits Reproduce; Integers Don't
  854. Radicals, Radicals, And More Radicals in an Inequality
  855. Radon's Inequality and Applications
  856. Ramsey's Number R(3, 3, 3)
  857. Ramsey Number R(4, 3)
  858. Ramsey Number R(5, 3)
  859. Ramsey Number R(4, 4)
  860. Ramsey's Theorem
  861. Random Walks [Java]
  862. Rascal Triangle
  863. Rational Solutions to xy = yx
  864. Rearrangement Inequality [JavaScript]
  865. Recombining Permutations [Java]
  866. Rectangle on a Chessboard [Java]
  867. Rectilinear Paradox
  868. Reflection Lemma [Java]
  869. Riemann Rearrangement Theorem
  870. Riemann Sphere and Möbius Transformation
  871. Riemann Sums - Function Integration [Java]
  872. Right Replacement [Java]
  873. Rolle's and Mean Value Theorems [Java]
  874. Rolle's Theorem in Action
  875. RomanoNorwegian Inequality
  876. Rooks on a Chessboard
  877. Roots and Tangents [GeoGebra]
  878. Round Robin Tournament
  879. Russell's Paradox
  880. Solve A Fourth Degree Equation
  881. Sophie Germain's Identity
  882. Square Root of 2 is Irrational, Proof 29
  883. Square Roots and Triangle Inequality
  884. Squares in Pascal's Triangle
  885. Squeeze Theorem
  886. Sum of Absolute Values [JavaScript]
  887. Sum of All Natural Numbers
  888. Sums of Binomial Reciprocals in Pascal's Triangle
  889. Squeeze (Sandwich, Pinching ...) Theorem (Lemma): an Example
  890. Scalar Product Optimization [JavaScript]
  891. Scheduling and Critical Path Algorithm [Java]
  892. Schur's Inequality
  893. Scrub Tile Puzzle [Java]
  894. Second Pair of Twin Inequalities: Twin 1
  895. Second Pair of Twin Inequalities: Twin 2
  896. Self-descriptive Strings [Java]
  897. Self-documenting Iterations [JavaScript]
  898. Self-reference
  899. Seven integers under 127 and their Ratios
  900. Seven Terms Periodic Sequence
  901. Shapley-Shubik Power Index [Java]
  902. Shapley-Shubik Power Index Calculator [Java]
  903. Shifting Digits and a Point of View
  904. Ship-Dock Theorem
  905. Shuttle Puzzle Practice II [Java]
  906. Sicherman Dice
  907. Sierpinski Gasket and Tower of Hanoi
  908. Sierpinski's Gasket and Dihedral Symmetry [Java]
  909. Sieve of Squares [Java]
  910. Σ2-n = Σn·2-n
  911. Signs and Sums in a Sequence [Java]
  912. Signs in a Matrix [Java]
  913. Simple But Uncommon Equation from 1968 IMO
  914. Simple Cellular Automaton [Java]
  915. Simple Graph Practice [Java]
  916. Simple Inequality with a Variety of Solutions
  917. Simple Inequality with Many Faces And Variables
  918. Simple Somos Sequence - a Russian Olympiad problem
  919. Simple Somos Sequence Calculator [Java]
  920. Simple Yet Uncommon Inequalities with Absolute Value
  921. Simpson Paradox [Java]
  922. $\sin 1^{\circ}+\sin {2^\circ}+\sin 3^{\circ}+\cdots+\sin 180^{\circ}=\tan 89.5^{\circ}$
  923. Sine And Cosine Are Continuous Functions
  924. Sine of a Sum Formula, Proof Without Words
  925. Single formula to express any integer with digits 0-9 each used just once
  926. Sitaru-Schweitzer Inequality
  927. Six Balls, Two Weighings
  928. Size of a Class: Two Viewpoints
  929. Sladjan Stankovik's Inequality In Four Variables
  930. Sladjan Stankovik's Inequality With Constraint
  931. Sladjan Stankovik's Inequality With Constraint II
  932. Slider Puzzles [Java]
  933. Solitaire in Two Colors [Java]
  934. Solutions of F(x)=x and F(F(x))=x [JavaScript]
  935. Solve - an Olympiad Problem - in Your Mind
  936. Solve xx3 = 3
  937. Solve cos²x + cos²2x + cos²3x = 1
  938. Solving an Equation with Inverse Functions
  939. Soriteses
  940. Sorting Algorithms
  941. Sperner's Theorem
  942. Splitting piles
  943. Square Root of 2 as a Continued Fraction
  944. Square root of 2 is irrational
  945. Star of David Theorems in Pascal Triangle
  946. Stars in Array
  947. Steinhaus' Problem [Java]
  948. Step into the Elliptic Realm
  949. Stern-Brocot Tree
  950. Straight Tromino on a Chessboard [Java]
  951. Structure of Hyperreal Numbers
  952. Subsets and Intersections
  953. Subtraction Game [Java]
  954. Sums of the Elements of Three Element Subsets [JavaScript]
  955. Sum of Three Squares [JavaScript]
  956. Sums and Products, a Generalization
  957. Sums, Products, and 1-1 Functions
  958. Sums of Geometric Series - Proofs Without Words [Java]
  959. Sums of Power Series
  960. Sums Of Successive Squares
  961. Sum without Adding
  962. Sums and Products [Java]
  963. Sums of powers of digits [Java]
  964. Superposition Principle
  965. Surreal Numbers
  966. Swapping Rows and Columns [Java]
  967. Sylvester's Problem
  968. Taking Games Seriously [Java]
  969. Tangential Chaos
  970. Telescoping Cubes
  971. Telescoping Squares
  972. Telescoping Sums and Series [JavaScript]
  973. Telescoping Tangents
  974. The ass and the mule [Java]
  975. The Averages of Sides and Angles in a Triangle
  976. The Basic Rules of Counting
  977. The Local-Global Principle
  978. The Regula Falsi - Iterated
  979. The Roads We Take
  980. The Size is in the Eyes of the Beholder
  981. Three Complex Numbers Satisfy Fermat's Identity For Prime Powers
  982. Three Dimensional Cross
  983. Three Junior Problems from Vietnam
  984. Three Variables, Three Constraints, Two Inequalities (Only One to Prove) - by Leo Giugiuc
  985. Tool for Constructing Orthogonal Latin Squares [Java]
  986. Tower of Hanoi, the Hard Way [Java]
  987. Train on Bridge [JavaScript]
  988. Tran Hoang Nam's Cyclic Inequality in Three Variables
  989. Transpositions
  990. Traveling Salesman Problem [Java]
  991. Treatise on Arithmetical Triangle
  992. Triangular numbers that are also square
  993. Trigonometric Identity for the Pi Day
  994. Trigonometric Inequality with Integrals
  995. A Trigonometric Inequality with Ordered Triple of Variables
  996. Trilateral Diagrams [Java]
  997. Trinary Tree(s) underlying Primitive Pythagorean Triples
  998. Tromino Puzzle: Deficient Squares [Java]
  999. Twenty five boys and twenty five girls around a table.
  1000. Twin Inequalities in Four Variables: Twin 1
  1001. Twin Inequalities in Four Variables: Twin 2
  1002. Two Constraints, One Inequality by Qing Song
  1003. Two Circles and a Limit [Java]
  1004. Two Colors in Two Rows [Java]
  1005. Two Cyclic Inequalities [JavaScript]
  1006. Two Equations in Three Variables [JavaScript]
  1007. Two Men of Tibet [Java]
  1008. Two-Parameter Solutions to Three Almost Fermat Equations
  1009. Two-Sided Inequality by Dorin Marghidanu
  1010. Two Problems by Kunihiko Chikaya
  1011. Two Problems from a Serbian 7 Grade Math Competition
  1012. Two Products: Constraint and Inequality
  1013. Two Sequences Defined by Recurrence
  1014. Two-Sided Inequality - One Provenance
  1015. Two Solutions: One Correct, One Illuminating. An Example
  1016. Uncountability of the Reals - via a Game
  1017. Undefined vs Indeterminate in Mathematics
  1018. (Un)fair Division by Consensus
  1019. Universal Coloring [Java]
  1020. Universal Product Code [Java]
  1021. Unproperty of the Powers of 2
  1022. Unsolved Problem from Crux Solved
  1023. USA 1975 Problem 3
  1024. Vasile Cirtoaje's Cyclic Inequality with Three Variables
  1025. Vandermonde's Convolution Formula
  1026. Vandermonde Determinant
  1027. Venn Diagrams
  1028. Viète's Formulas
  1029. Voronoi Diagram [JavaSCript]
  1030. Ways To Count
  1031. Weierstrass Product Inequality
  1032. Weierstrass Substitution
  1033. What, how, and the Web [Java]
  1034. What 1, 6, and 14 Have to Do with 5?
  1035. What Is Algorithm?
  1036. What Is Determinant?
  1037. What Is Finite?
  1038. What Is Infinite Descent?
  1039. What Is Infinity?
  1040. What Is Limit?
  1041. What is so natural about "natural logarithms"?
  1042. What Is Space Completion?
  1043. WHEN THE COUNTING GETS TOUGH, THE TOUGH COUNT ON MATHEMATICS
  1044. When Two Segments Intersect? [JavaScript]
  1045. Where To Start? [Java]
  1046. White and Black Balls in Urn. 1 in, 2 out. What Color Remains?
  1047. Why 17?
  1048. Why Can't They Be All Different?
  1049. Why sin(x)/x tends to 1
  1050. Why The Number of Primes Could Not Be Finite?
  1051. Wilson's Theorem
  1052. Without Definitions: Why $\displaystyle\frac{1}{3}+\frac{2}{5}=\frac{11}{15}?$
  1053. Wonderful Inequality on Unit Circle
  1054. Word Problems [Java]
  1055. Wu's Inequality
  1056. $x_n=\sin 1+\sin 3+\sin 5+\cdots+\sin (2n-1)$
  1057. Yet Another Puzzle with Hats
  1058. Yet Another Simple Integral
  1059. Zeros and Nines [Java]

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