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Leonhard Euler
eiπ + 1 = 0 Leonhard Euler (1707–1783)

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History of Mathematics · Augustin-Louis Cauchy: the rigour of analysis

Image credits

Historical images and photographs All come from Wikimedia Commons. We use the files or thumbnails provided by Commons, reduced to at most …

History of Mathematics · Augustin-Louis Cauchy: the rigour of analysis

The legacy of Augustin-Louis Cauchy

Cauchy is mad, and there is nothing to be done with him; and yet he is, at present, the one who knows how mathematics ought to be done. — …

History of Mathematics · Augustin-Louis Cauchy: the rigour of analysis

Stress in elastic solids

Cauchy never stopped being an engineer. In 1822 Claude-Louis Navier had presented to the Academy a theory of elastic solids based on forces …

History of Mathematics · Augustin-Louis Cauchy: the rigour of analysis

The integral in the complex plane

At the end of the eighteenth century, Euler and Laplace computed hard real integrals with a daring trick: they replaced the real variable …

History of Mathematics · Augustin-Louis Cauchy: the rigour of analysis

The derivative and the integral

Two years after the Cours d’analyse, Cauchy published the Résumé des leçons données à l’École royale polytechnique sur le calcul …

History of Mathematics · Augustin-Louis Cauchy: the rigour of analysis

Cauchy's inequality

The 1821 Cours d’analyse ends with nine notes, a kind of appendix with results Cauchy did not want to put in the main text. The second, on …

Leonhard Euler

Leonhard Euler · 1707–1783

Why “Euler's Eyes”?

Leonhard Euler was one of the most prolific mathematicians in history. Around 1738 he lost almost all sight in his right eye after years of cartography work for the Saint Petersburg Academy, and in 1766 a cataract was found in his left eye. Nearly blind, he kept going: about half of his work was written after that, often dictated from memory.

Read Euler, read Euler, he is the master of us all.

Pierre-Simon Laplace

The site’s name honours that way of seeing mathematics: clearly, even when the eyes fail. Here you will find step-by-step explanations and solved exams, written for people who are learning.

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