Search found 188 matches

by sakibtanvir
Sat Oct 20, 2012 2:28 pm
Forum: Chemistry
Topic: More preferable Fuel
Replies: 7
Views: 5951

Re: More preferable Fuel

Hope this will help. ;)
http://bit.ly/XCQxfT
by sakibtanvir
Thu Oct 18, 2012 2:36 pm
Forum: Secondary Level
Topic: a trigonometry problem
Replies: 2
Views: 1281

Re: a trigonometry problem

I am confused about the question :? .Why this $"\beta"$ angle is a variable when the equations tell,
$\displaystyle \sin \beta = \pm \sqrt {\frac{-1 \pm \sqrt {65}}{32}}$.But if the complex angles(!) are not allowed,then,
$\displaystyle \sin \beta = \pm \sqrt{\frac{-1+ \sqrt {65}}{32}}$. :|
by sakibtanvir
Wed Oct 17, 2012 11:04 pm
Forum: Junior Level
Topic: Find positive integers
Replies: 4
Views: 1996

Re: Find positive integers

Yes,the only solutions are $(a,b)=(1,998),(998,1)$. It is easy to notice one of the variables $(a,b)$ is odd and another is even.WLOG let us assume $b=2k$(even). Case1:When $a \leq 1$,the only solutions found by a little investigation is $(a,b)=(1,998),(998,1)$. Case2:When $a,b >1$,$a^{2k}+(2k)^{a}=...
by sakibtanvir
Wed Oct 17, 2012 2:16 pm
Forum: Geometry
Topic: Triangle
Replies: 13
Views: 5370

Re: Triangle

At first prove that,$PCQR$ is a rhombus. (Hint: Use congruence of triangles and the Angle Bisector Theorem) $\Delta PQR \cong \Delta PCQ$.[Because,$RQ=QC,PR=PC$ and $PQ$ is a common side.].Let,$O$ be the intersection point of $RC$ and $PQ$. $\therefore \angle RPQ=\angle CPQ,\angle RQP=\angle CQP$.In...
by sakibtanvir
Wed Oct 17, 2012 1:48 pm
Forum: Geometry
Topic: Triangle
Replies: 13
Views: 5370

Re: Triangle

I have found a generalized proof already. :D
by sakibtanvir
Tue Oct 16, 2012 11:06 pm
Forum: Geometry
Topic: Triangle
Replies: 13
Views: 5370

Re: Triangle

Is $\Delta ABC$ acute angled or it's not mentioned in the question? I asked this because the proof can be easily obtained then. :)
by sakibtanvir
Mon Oct 15, 2012 4:33 pm
Forum: Combinatorics
Topic: n x n board
Replies: 10
Views: 4861

Re: n x n board

Sorry,but how??? :o :o :o .Check if I am misunderstanding.
If you just paint the field of the left bottom corner, the others have no green field at all or having 0(even) greens.
by sakibtanvir
Sun Oct 14, 2012 4:44 pm
Forum: Combinatorics
Topic: n x n board
Replies: 10
Views: 4861

Re: n x n board

Okay,Draw a $n \times n$ board where $n$ is even. Now choose all the fields of the leftmost column and the bottom-most row.So, $2n-1$ fields are chosen.Now however You paint them green, it satisfies neither $(a)$ nor $(b)$.If it really happens,then problem becomes a fallacy. :?
by sakibtanvir
Wed Oct 10, 2012 2:19 pm
Forum: Junior Level
Topic: Easy-quizy
Replies: 6
Views: 2892

Re: Easy-quizy

sowmitra wrote:Well, there are many approaches. I tried Appolonius' Theorem. Similarity also gives a nice solution.
I also used Apollopnius for the reverse proof.But these proofs are smarter!
by sakibtanvir
Tue Oct 09, 2012 2:25 pm
Forum: Junior Level
Topic: Easy-quizy
Replies: 6
Views: 2892

Easy-quizy

That is easy but not a spoiler!,I think.
Problem: In $\Delta ABC$, $D$ and $E$ are the midpoints of $AB$ and $AC$ respectively.Prove that, $AB=AC$ if and only if $BE=CD$ .