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Đào Thanh Oai's user avatar
Đào Thanh Oai's user avatar
Đào Thanh Oai's user avatar
Đào Thanh Oai
  • Member for 6 years, 8 months
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suggested
Approve
An inequality in cyclic polygon and tangential polygon
revised
A generalization of Barrow's inequality
deleted 15 characters in body
revised
A generalization of Barrow's inequality
added 82 characters in body
asked
A generalization of Barrow's inequality
asked
Triangle centers formed a rectangle associated with a convex cyclic quadrilateral
comment
Can four integer numbers $x$, $y$, $x-y$, $x+y$ be powerful numbers where $\gcd(x,y)=1$?
My email: [email protected]
comment
Can four integer numbers $x$, $y$, $x-y$, $x+y$ be powerful numbers where $\gcd(x,y)=1$?
@NoamD.Elkies What is your email? can I get Your email to discuss some ideas. Hopefully, when discussing with him, we can build a general rule for equation with finite solutions. My email in next comment
comment
Continuing generalization of the Simson line
May you write detail your result?
awarded
 Nice Question
comment
Can exist a positive integer number $x$ such that $a_1=x$ and $a_n=2a_{n-1}+1$ are not prime for all $n \ge 1$?
@ClaudeChaunier Thanks you very much. Maybe my program fail or not accuracy.
asked
Can exist a positive integer number $x$ such that $a_1=x$ and $a_n=2a_{n-1}+1$ are not prime for all $n \ge 1$?
comment
Can four integer numbers $x$, $y$, $x-y$, $x+y$ be powerful numbers where $\gcd(x,y)=1$?
I have just checked, there are no solution for first 10000 powerful number ($x+y \le 23002083$).
comment
Can four integer numbers $x$, $y$, $x-y$, $x+y$ be powerful numbers where $\gcd(x,y)=1$?
@DanielWeber Oh, let $y=1$, this question degenerate to Can three consecutive numbers be powerful?
asked
Can four integer numbers $x$, $y$, $x-y$, $x+y$ be powerful numbers where $\gcd(x,y)=1$?
comment
Relation of some Euclidean geometry theorems and more conjecture generalizations
@FedorPetrov Second Ptolemy's theorem also is speial case of Feuerbach-Luchterhand theorem (let $P\equiv O$) center of the circumcircle.
awarded
 Excavator
comment
Relation of some Euclidean geometry theorems and more conjecture generalizations
@FedorPetrov I update: Ptolemy's theorem is special case of Feuerbach-Luchterhand theorem
awarded
 Organizer
revised
Relation of some Euclidean geometry theorems and more conjecture generalizations
Show that Ptolemy theorem is special case of Feuerbach-Luchterhand
suggested
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Relation of some Euclidean geometry theorems and more conjecture generalizations
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