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#1 Re: Help Me ! » all trees planar? » 2010-10-12 21:57:51

Ok, I might be getting somewhere.

A graph is planar if it can be drawn without edges that intersect within a plane. I believe this is true for all trees, right?

Do I use Euler's formula: v-e+f=2 where for a tree, f=1?

#2 Help Me ! » all trees planar? » 2010-10-12 19:58:17

boy15
Replies: 2

Hey guys, I am learning about trees and one of the questions from my book what to prove that all trees are bipartite (so they are 2-colorable). I did this fine by induction but the next question says:

"Are all trees therefore planar?" Explain your answer.

I am not sure how to go about this. Any help would be awesome, thanks.

#3 Re: Help Me ! » exact solution to heat equation » 2010-10-11 12:49:05

nha wrote:

Am I supposed to find

which gives the exact solution at points on the grid, and that
and
. I can't find what
is.

I think you need to find T(j,n), but I don't know what the exact solution is. I guess you will have to wait for a moderator to answer, bobbym should be able to help you.

boy15

#4 Re: Help Me ! » sequences help » 2010-08-31 14:52:11

mathsyperson: Thanks heaps, I was over complicating q2. I understand it now.

TheDude: Yeah, I missed that, I normally see it a_n/a_{n+1), but I understand it all now.

Thank you TheDude and mathsyperson for helping me.

#5 Re: Help Me ! » sequences help » 2010-08-30 23:09:34

TheDude wrote:

Thanks for the help, but I don't really understand how

.

Yeah, I think it question 2 should be interpreted your way but I still can't do anything with it. Can someone help with q2 please?

#6 Help Me ! » sequences help » 2010-08-30 02:01:22

boy15
Replies: 5

Hi everyone, I need some help on some sequences questions. I tried them, but failed bad.

1. Prove that the function:

converges whenever the following holds: 


2.


If
for all
and
, then what are the
?

Any help on either of these question would be greatly appreciated. I tried 1, but I could not get the limit to evaluate to a finite number, I must be doing it wrong.

#7 Re: Help Me ! » induction questions » 2010-08-24 21:26:11

bob bundy wrote:

Hi,

Fibonacci question.

Can you show that any number can be written as the sum of two smaller numbers without using the same FB number twice?

If the theorem is true for the two smaller numbers then its true for their sum.  This is what you've got to show.

Thanks for the help bob once again, so I show the base step a=1: a=1=F(b_1)=1
But how do I use proper notation for the induction step a+1?

#8 Help Me ! » induction questions » 2010-08-24 01:00:28

boy15
Replies: 4

Hey everyone, I am finding induction a bit hard so if anyone could help me with these 2 questions it would be much appreciated.

Use strong mathematical induction to prove that there exists positive integers a, b, c satisfying

for
.

Using mathematical induction, prove that any positive integer a may be expressed as a sum of Fibonacci numbers


where none of the
's are repeated in the sum.

If you could show me what to do that would be great.
Thanks

#9 Re: Help Me ! » dual of 27-gon? » 2010-08-24 00:44:03

That helped alot. Thanks again Bob. smile

#10 Help Me ! » dual of 27-gon? » 2010-08-22 11:48:36

boy15
Replies: 3

Hey everyone, can anybody help me out here, I don't know what the dual of a regular 27-gon is.

Thanks

#11 Re: Help Me ! » Discrete math help » 2010-08-22 11:46:37

Thanks all, I understand now.

#12 Help Me ! » Discrete math help » 2010-08-15 12:58:53

boy15
Replies: 5

Hi, I need help on a problem from my discrete math textbook.

If


is a polynomial with integer coefficients, and that this polynomial takes the value zero at four distinct integer values a, b, c and d.

Show that there exists no integer value n for which

.

I don't know how to do it and my book doesn't go through it well enough. Can anyone help me?

Thanks

#13 Help Me ! » Vector help! » 2010-03-29 10:21:29

boy15
Replies: 0

Don't worry, I did it! smile

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