# Questions tagged [fermat]

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### 17th or 18th century use of the continued fraction expansion of $(1 + \sqrt D)/2$ to solve the diophantine equation $x^2 - D y^2 = 4$

Can someone please provide an early reference to the use of the continued fraction expansion of $\frac{1+\sqrt D}2$ to solve the Diophantine equation $x^2 - D y^2 = 4$ for a positive integer $D$ ...
1 vote
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### What physical problems required the invention of the derivative?

I know that Fermat had a method of adequality in order to solve certain optimization. One such problem was: "Suppose that you have a rectangle of material and need to cut corners into it such ...
• 491
1 vote
126 views

### Fermat et l'équation de Pell

Does any of you happen to own and electronic copy of the paper "Fermat et l'équation de Pell" by A. Weil? If I understand correctly, this paper can be found on pages 413-419 of the third ...
• 1,787
193 views

### Does Fermat's Principle of Least Time imply that he believed light moved at a finite speed?

And if so, how did he imagine that light moved at different speeds in different media?
• 1,111
1 vote
129 views

### How did Fermat come up with his Last Theorem?

It's usually believed that Fermat's claim that he had a proof for the Last Theorem is false, and that it might have been more of a conjecture. Or considering it took many centuries and advanced ...
• 111
1 vote
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### How did Fermat find tangent lines of Folium of Descartes?

The wikipedia article about Folium of Descartes says: Descartes challenged Pierre de Fermat to find the tangent line to the curve at an arbitrary point since Fermat had recently discovered a method ...
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### Is the story about Fermat's writing on a margin true?

Is there any evidence that Fermat wrote on the margin of a book "I have discovered a truly marvelous demonstration of this proposition that this margin is too narrow to contain." Everyone ...
• 375
832 views

### What did Fermat do as a lawyer?

Fermat is easily one of the best known mathematicians of all time. We all know about Fermat's Last Theorem, Fermat's Little Theorem, his quadrature rule, his invention of probability theory, etc. ...
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### Did Kepler influence Fermat?

On page 347 in his "Mathematical Thought, volume 1", Morris Kline writes: "The work on the third class of problems, finding the maxima and minima of functions, may be said to begin with an ...
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