Fork me on GitHub

planetmath.org

Math for the people, by the people.

Welcome!

PlanetMath is a virtual community which aims to help make mathematical knowledge more accessible. PlanetMath's content is created collaboratively: the main feature is the mathematics encyclopedia with entries written and reviewed by members. The entries are contributed under the terms of the Creative Commons By/Share-Alike License in order to preserve the rights of authors, readers and other content creators in a sensible way. We use LaTeX, the lingua franca of the worldwide mathematical community.

Beginning February 23th 2015 we experienced 15 days of downtime when our server stopped working. We moved a backup to DigitalOcean, and we're back online. Some features aren't working yet; we're restoring them ASAP. Please report bugs in the Planetary Bugs Forum or on Github.

User login



Latest Messages  

[p] Another good book by akdevaraj Mar 27
"Prime obsession " by John Derbyshire - it is on Riemann Hypothesis- extremely readable.

pstricks by Wkbj79 Mar 15
>

[p] Deleting by akdevaraj Feb 15
How do we delete a message; I clicked on edit.then tried to delete but did not succeed.

[p] Indirect primality testing by perucho Feb 15
Thanks akdevaraj for clarify what "*" means. k* confused me since here in PM one simply writes f(x+kf(x)). Your example is quite complex, so f(x+kf(x)) is too long. But let's suppose f(x)=x^2, so f(x+kf(x))=f(x+kx^2)=(x+kx^2)^2=k^2x^4+2kx^3+x^2. Let's prove a couple of examples. If k=0, f(x+0f(x))=0^2x^4+2(0)x^3+x^2=x^2=f(x) as it should be. If k=1, f(x+1f(x))=1^2x^4+2(1)x^3+x^2=x^2+2x^3+x^4=(x+x^2)^2=f(x+x^2), again as it should be. Thus I can't understand what you are trying to do. Greetings.

[p] Approximate values of real by RKJCHENNAI Feb 11
http://rkmath.yolasite.com/resources/Roots%20sum%20and%20multiplication.pdf

Finding approximate values of real roots equation. by RKJCHENNAI Feb 11
>

[p] search engine by akdevaraj Feb 4
Search engine still not functioning!

[p] Legendre's symbol by akdevaraj Jan 29
(a/p) is the Legendre symbol for quadratic residues and non-residues. If (a/p) = -1 it means a is not a quadratic residue of p. Another way of expressing this: the p (under ref ) is an impossible prime factor of (x^2 - a ).For further examples of this concept see A123239, A 072936 and A 119691 on OEIS.

[p] Book by akdevaraj Jan 26
Currently reading "prime numbers - a computational perspective" by Richard Crandall and Carl Pomerance. This is a monumental book on prime numbers, primality testing and factorisation.

[p] Book by akdevaraj Jan 26
Currently reading "prime numbers - a computational perspective" by Richard Crandall and Carl Pomerance. This is a monumental book on prime numbers, primality testing and factorisation.

[p] Book by akdevaraj Jan 26
Currently reading "prime numbers - a computational perspective" by Richard Crandall and Carl Pomerance. This is a monumental book on prime numbers, primality testing and factorisation.

[p] Indirect primality testing by akdevaraj Jan 24
Dear dh2718, thanks for the compliment.

[p] Indirect primality testing by akdevaraj Jan 23
Dear Permalink-you are right about bio-age; I am 85.

[p] Indirect primality testing by akdevaraj Jan 13
Dear Peruchio - f(x+k*f(x)) - star means "multiply". k belongs to Z Thus in this case since f(x) = x^2+x+1, f(x+k*f(x)) means 1 + 3k. Trust this is clear.