Search found 9 matches
- Mon Apr 13, 2015 8:48 pm
- Forum: Number Theory
- Topic: a problem of number theory
- Replies: 2
- Views: 3488
Re: a problem of number theory
thanks for giving solution
- Tue Jan 07, 2014 8:17 pm
- Forum: Number Theory
- Topic: Nice In a Tricky Way!
- Replies: 2
- Views: 3785
Re: Nice In a Tricky Way!
from tahmid ,so there are no $n$ except 1 that follows masum's equation.
- Wed Dec 25, 2013 11:09 am
- Forum: Geometry
- Topic: O And H Are Isogonal Conjugates(simple)
- Replies: 3
- Views: 3324
Re: O And H Are Isogonal Conjugates(simple)
my solution using dilatation:
by rotation ,$AO$ concides $AH$ ,$E$ is on $AB$,$D$ is on $AC$
then,triangle $O'E'D'$ is dilatated by triangle $OED$. ;$O'E'D'$ is orthic triangle of $ABC$.
now we know that orthocenter is incenter of orthic triangle.
then $\angle EOA=\angle DOA$.
by rotation ,$AO$ concides $AH$ ,$E$ is on $AB$,$D$ is on $AC$
then,triangle $O'E'D'$ is dilatated by triangle $OED$. ;$O'E'D'$ is orthic triangle of $ABC$.
now we know that orthocenter is incenter of orthic triangle.
then $\angle EOA=\angle DOA$.
- Sun Dec 22, 2013 8:32 am
- Forum: Geometry
- Topic: O And H Are Isogonal Conjugates(simple)
- Replies: 3
- Views: 3324
Re: O And H Are Isogonal Conjugates(simple)
Thank you (vai) for hints
- Mon Dec 09, 2013 11:21 am
- Forum: Chemistry
- Topic: Help please!
- Replies: 2
- Views: 10363
Re: Help please!
Tolen reagent means a solution of AgNO3+NH4OH
Aldehyde means functional group ' >CHO ' included organic compound.
Aldehyde means functional group ' >CHO ' included organic compound.
- Mon Dec 09, 2013 10:10 am
- Forum: Geometry
- Topic: O And H Are Isogonal Conjugates(simple)
- Replies: 3
- Views: 3324
O And H Are Isogonal Conjugates(simple)
points $O$ and $H$ are the circumcenter and the orthocenter of acute triangle $ABC$ ,respectively.The perpendicular bisector of segment $AH$ meets $AB$ and $AC$ at $D$ and $E$ ,respectively.
Prove that $\angle DOA=\angle EOA$.
Prove that $\angle DOA=\angle EOA$.
- Wed Nov 27, 2013 9:47 pm
- Forum: Number Theory
- Topic: Simple problem[don't try]
- Replies: 3
- Views: 4072
Re: Simple problem[don't try]
Thanks for reply.But you only count between 'n' and '2n' . you have to also count for less then 'n'.
- Sun Nov 24, 2013 11:22 pm
- Forum: Number Theory
- Topic: Simple problem[don't try]
- Replies: 3
- Views: 4072
Simple problem[don't try]
Let n be a positive integer.
2. find the sum of all positive intergers less then 2n and relatively prime to n.
2. find the sum of all positive intergers less then 2n and relatively prime to n.
- Tue Aug 27, 2013 6:41 pm
- Forum: Number Theory
- Topic: a problem of number theory
- Replies: 2
- Views: 3488
a problem of number theory
Let N be a number with 9 distinct non-zero digits,such that ,for each k from 1 to 9 inclusive,the first k digits of N form a number which is divisible by k.Find N.