Search found 23 matches

Tue Jan 13, 2015 10:50 pm
Forum: Combinatorics
Topic: n+1 rows and columns
Replies: 10
Views: 2016

Re: n+1 rows and columns

Actually I wanted to count the number of black cells we need "at least" & present them as the intersections so that i can prove there "always" exists $i$ rows & $j$ columns with given condition.
Sun Jan 11, 2015 11:08 pm
Forum: Combinatorics
Topic: n+1 rows and columns
Replies: 10
Views: 2016

Re: n+1 rows and columns

We want to colour the least possible cells in black so that all the $n!$ sets may have at least one black cell. And this is possible by colouring all the cells of a row/column black. Now each cell can be described as the intersection of a row and a column. In the above case where we wanted to colour...
Fri Jan 09, 2015 8:41 pm
Forum: Junior Level
Topic: Birthday Cake
Replies: 3
Views: 2283

Re: Birthday Cake

Well, not giving the answer directly.
You know, one can eat more than one piece but not a fractional portion of a piece.
Tue Oct 14, 2014 11:38 pm
Forum: Number Theory
Topic: Arithmetic series in Fibonacci
Replies: 5
Views: 1323

Re: Arithmetic series in Fibonacci

But subsequence does not necessarily need to be of consecutive terms of the original sequence, does it?
Wed Oct 01, 2014 11:24 pm
Forum: Number Theory
Topic: Dat cool problem
Replies: 3
Views: 962

Re: Dat cool problem

I think the term was $\frac{{a_{i-1}}^2+{a_i}^2}{2}$ in our exam!
Fri Sep 19, 2014 12:06 pm
Forum: Number Theory
Topic: Magic-Square preserving functional equation(Self-made)
Replies: 4
Views: 1006

Re: Magic-Square preserving functional equation(Self-made)

Anyway, you can only divide by r, if this is a common factor of all the entries!
Fri Sep 19, 2014 11:12 am
Forum: Number Theory
Topic: Magic-Square preserving functional equation(Self-made)
Replies: 4
Views: 1006

Re: Magic-Square preserving functional equation(Self-made)

If we have a $n*n$ magic square with entries $(a_1, a_2,..., a_{n^2})$ , we can simply make another magic square with entries $(a_1\pm r, a_2\pm r,..., a_{n^2}\pm r)$ , where $r$ is a positive integer. because then the sum of each row or column will be increased or decreased by $nr$ . And the same g...
Tue Sep 03, 2013 7:30 pm
Forum: News / Announcements
Topic: Online Geometry Camp 2014 Phase 1
Replies: 19
Views: 5865

Re: Online Geometry Camp 2014 Phase 1

@নায়েল ভাইয়া,

আমাদের যে দুই টা পরীক্ষা হল, এগুলোর ফলাফল কি জানানো হবে? হলে কবে?
Sat Aug 31, 2013 8:32 pm
Forum: National Math Camp
Topic: [OGC1] Online Geometry Camp: Day 5 (EXAM!)
Replies: 29
Views: 5275

Re: [OGC1] Online Geometry Camp: Day 5 (EXAM!)

nayel wrote:Ira, did you email or pm me your solutions? I've checked both but can't seem to find them.

Nayel vaia, I have sent you email. it is still in my sent item.
As you didn't find it. I am resending.
Sat Aug 31, 2013 6:32 pm
Forum: National Math Camp
Topic: [OGC1] Online Geometry Camp: Day 5 (EXAM!)
Replies: 29
Views: 5275

Re: [OGC1] Online Geometry Camp: Day 5 (EXAM!)

nayel wrote:I've replied to everyone who has sent me solutions. If you didn't get a reply, let me know asap.
vaia, I have received a reply for Exam 02. but didn't get for Exam 01. Did you get my solutions of Exam 01?