algebra
https://plus.maths.org/content/taxonomy/term/366
enSolving quadratics in pictures
https://plus.maths.org/content/solving-quadratics-pictures
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<img class="imagefield imagefield-field_abs_img" width="100" height="100" alt="" src="https://plus.maths.org/content/sites/plus.maths.org/files/abstractpics/5/5_nov_2014_-_1730/babylonian_icon.jpg?1415208613" /> </div>
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<p>How to derive the famous quadratic formula from pictures, just like the Babylonians did.</p>
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<div style="float: right; width: 40%"><div class="centreimage" ><img src="https://plus.maths.org/content/sites/plus.maths.org/files/blog/102014/babylonian.jpg" alt="" width="250" height="259"/>
<p>A Babylonian inscription from around 2800 BC.</p><p><a href="https://plus.maths.org/content/solving-quadratics-pictures" target="_blank">read more</a></p>https://plus.maths.org/content/solving-quadratics-pictures#commentsalgebrageometryhistory of mathematicsquadratic equationFri, 07 Nov 2014 10:32:29 +0000mf3446230 at https://plus.maths.org/contentThomas Harriot: A lost pioneer
https://plus.maths.org/content/thomas-harriot-lost-pioneer
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Anna Faherty </div>
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<img class="imagefield imagefield-field_abs_img" width="100" height="100" alt="" src="https://plus.maths.org/content/sites/plus.maths.org/files/issue50/features/faherty/icon.jpg?1235865600" /> </div>
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It's International Year of Astronomy and all eyes are on Galileo Galilei, whose astronomical observations 400 years ago revolutionised our understanding of the Universe. But few people know that Galileo wasn't the first to build a telescope and turn it on the stars. That honour falls to a little-known mathematician called Thomas Harriot, who excelled in many other ways too. <b>Anna Faherty</b>
takes us on a tour of his work. </div>
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<div class="pub_date">March 2009</div>
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<p><i>It's International Year of Astronomy and all eyes are on Galileo Galilei, whose astronomical observations 400 years ago revolutionised our understanding of the Universe. But few people know that Galileo wasn't the first to build a telescope and turn it on the stars. That honour falls to a little-known mathematician called Thomas Harriot, who might have become a household name, had he
bothered to publish his results. This article is a tour of his work.</i></p><p><a href="https://plus.maths.org/content/thomas-harriot-lost-pioneer" target="_blank">read more</a></p>https://plus.maths.org/content/thomas-harriot-lost-pioneer#comments50algebraastronomybinary numberKepler's conjecturerefractionsnell's lawSun, 01 Mar 2009 00:00:00 +0000plusadmin2351 at https://plus.maths.org/contentA tale of two curricula: Euler's algebra text book
https://plus.maths.org/content/tale-two-curricula-eulers-algebra-text-book
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Chris Sangwin </div>
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<img class="imagefield imagefield-field_abs_img" width="100" height="100" alt="" src="https://plus.maths.org/content/sites/plus.maths.org/files/issue45/features/sangwin/icon.jpg?1196467200" /> </div>
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In the fourth and final part of our series celebrating 300 years since Leonhard Euler's birth, we let Euler speak for himself. <b>Chris Sangwin</b> takes us through excerpts of Euler's algebra text book and finds that modern teaching could have something to learn from Euler's methods. </div>
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<div class="pub_date">December 2007</div>
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<p><i>"It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to Heaven, we were all
going direct the other way — in short, the period was so far like the present period, that some of its noisiest author<p><a href="https://plus.maths.org/content/tale-two-curricula-eulers-algebra-text-book" target="_blank">read more</a></p>https://plus.maths.org/content/tale-two-curricula-eulers-algebra-text-book#comments45algebracomplex numberEulerEuler yearirrational numberquadratic equationSat, 01 Dec 2007 00:00:00 +0000plusadmin2320 at https://plus.maths.org/contentEditorial
https://plus.maths.org/content/pluschat-21
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<img class="imagefield imagefield-field_abs_img" width="98" height="100" alt="" src="https://plus.maths.org/content/sites/plus.maths.org/files/abstractpics/1/May%2019%2C%202010/plusbirthdaycakeSmall.jpg?1274279790" /> </div>
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<p>The <em>Plus</em> anniversary year — A word from the editors</p>
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<div class="pub_date">December 2007</div>
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<h2>This issue's <i>Plus</i>chat topics</h2>
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<li><a href="#blurb">The <i>Plus</i> anniversary year</a> — A word from the editors;</li>
<li><a href="#plus10000"><i>Plus</i> 10,000</a> — The best maths ever.</li>
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<h3>The <i>Plus</i> anniversary year — A word from the editors</h3>
<p>This is the last issue of 2007 and, sadly, it's time to wrap up <i>Plus</i>'s tenth birthday party.<p><a href="https://plus.maths.org/content/pluschat-21" target="_blank">read more</a></p>45Al-KhwarizmialgebraeditorialEuclid's ElementsEuclidean geometrygeometrygolden ratiohyperbolic geometryirrational numbernumber systemplus birthdaypythagoras' theoremZeno's paradoxesSat, 01 Dec 2007 00:00:00 +0000plusadmin4901 at https://plus.maths.org/contentAn enormous theorem: the classification of finite simple groups
https://plus.maths.org/content/enormous-theorem-classification-finite-simple-groups
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Richard Elwes </div>
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<b>Winner of the general public category</b>. Enormous is the right word: this theorem's proof spans over 10,000 pages in 500 journal articles and no-one today understands all its details. So what does the theorem say? <b>Richard Elwes</b> has a short and sweet introduction. </div>
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<div class="pub_date">December 2006</div>
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<p style="color:purple;"><b><i>This article is the winner of the general public category of the Plus new writers award 2006.</i></b></p>
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<div class="leftimage" style="width: 200px;"><img src="/issue41/features/elwes/gorenstein.jpg" alt="Daniel Gorenstein" width="200" height="275" />
<p>Daniel Gorenstein</p><p><a href="https://plus.maths.org/content/enormous-theorem-classification-finite-simple-groups" target="_blank">read more</a></p>https://plus.maths.org/content/enormous-theorem-classification-finite-simple-groups#comments41algebragroup theorysymmetryThu, 07 Dec 2006 00:00:00 +0000plusadmin2293 at https://plus.maths.org/contentThe power of groups
https://plus.maths.org/content/power-groups
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Colva Roney-Dougal </div>
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Groups are some of the most fundamental objects in maths. Take a system of interacting objects and strip it to the bone to see what makes it tick, and very often you're faced with a group. <b>Colva Roney-Dougal</b> takes us into their abstract world and puzzles over a game of Solitaire. </div>
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<div class="pub_date">June 2006</div>
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<p><i>"I am searching for abstract ways of expressing reality, abstract forms that will enlighten my own mystery."</i> Eric Cantona, footballer.</p><p><a href="https://plus.maths.org/content/power-groups" target="_blank">read more</a></p>https://plus.maths.org/content/power-groups#comments39algebragroup theoryWed, 31 May 2006 23:00:00 +0000plusadmin2283 at https://plus.maths.org/contentAgainst the odds
https://plus.maths.org/content/against-odds
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Danielle Stretch </div>
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<img class="imagefield imagefield-field_abs_img" width="130" height="130" alt="" src="https://plus.maths.org/content/sites/plus.maths.org/files/issue12/features/noether/icon.jpg?967762800" /> </div>
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<strong>Danielle Stretch</strong> looks back at the remarkable life of pioneering mathematician Emmy Amalie Noether (1882-1935). Despite her constant struggles to make her way in a man's world, she made significant contributions to the development of modern algebra. </div>
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<div class="pub_date">September 2000</div>
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<h2>Emmy Amalie Noether</h2>
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<p>Emmy Amalie Noether was born on March 23rd 1882 to a middle class Jewish family in the small Bavarian town of Erlangen. Her father, <a href="http://www-history.mcs.st-andrews.ac.uk/history/Mathematicians/Noether_Max.html">Max Noether</a>, was a distinguished professor of mathematics at the University of Erlangen.</p><p><a href="https://plus.maths.org/content/against-odds" target="_blank">read more</a></p>https://plus.maths.org/content/against-odds#comments12algebraEmmy Noetheridealnoether's theoremringwomen in mathematicsThu, 31 Aug 2000 23:00:00 +0000plusadmin2173 at https://plus.maths.org/contentThree-digit numbers
https://plus.maths.org/content/three-digit-numbers
<div class="pub_date">May 1998</div>
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<p>A three-digit number is such that its second digit is the sum of its first and third digits.</p>
<p><b>Prove</b> that the number must be divisible by 11.</p>
<h3><a href="/issue5/puzzle/digits.html">Solution</a></h3>
https://plus.maths.org/content/three-digit-numbers#commentsalgebrapuzzleThu, 30 Apr 1998 23:00:00 +0000plusadmin2949 at https://plus.maths.org/content