Federico Ramponi
  • Member for 11 years, 4 months
  • Last seen more than 9 years ago
Do complex numbers really exist?
23 votes

Here is an example of a physical quantity which comes naturally as a complex number. The impedance between two nodes of a linear electrical circuit working in alternate current, which is the ...

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Where to start learning Linear Algebra?
19 votes

I'll add another title (it's a bit on the theoretical side, but still at the introductory level, very readable and definitely worth): Serge Lang, Linear algebra 3rd. ed., Springer

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A challenge by R. P. Feynman: give counter-intuitive theorems that can be translated into everyday language
13 votes

"The natural numbers are as many as the even natural numbers". This statement is trivial and not worth to be named "theorem", but it is rather counterintuitive if you don't know the meaning of "as ...

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Alternate definition of prime number
6 votes

As far as I know, your definition A prime is an element p such that whenever p divides ab, then either p divides a or p divides b, is the true definition of "prime". The usual one, ... an ...

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What are the recommended textbooks for introductory calculus?
3 votes

If you can get a copy (which is improbable, I'm afraid), Vladimir Smirnov, A Course of Higher Mathematics, VOLUME 1, Pergamon press 1964. This is a translation of a beautiful treatise on ...

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How to reduce lower one number, while another number increases goes up increments
1 votes

Here is how you can construct a linear relation for general bounds: If $x$ goes from $a$ to $b$, then $x-a$ goes from $0$ to $b-a$, then $\frac{x-a}{b-a}$ goes from $0$ to $1$, then $(x-a) \frac{d-c}{...

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