
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
March 7th, 2010, 03:44 AM  #1 
Newbie Joined: Mar 2010 Posts: 2 Thanks: 0  mathematic induction
Hello, I don't know how to continue: Prove by mathematical induction that http://img230.imageshack.us/img230/6089/46951789.png is divisible by 6. I thought you have to use n = n+1 but I don't know how to continue. Does somebody know? thanks 
March 7th, 2010, 04:10 AM  #2 
Senior Member Joined: Apr 2008 Posts: 435 Thanks: 0  Re: mathematic induction
If you show me what you have so far, I'll do my best to help. 
March 7th, 2010, 05:28 AM  #3 
Newbie Joined: Mar 2010 Posts: 2 Thanks: 0  Re: mathematic induction
Firstly, I did n = 1 so 5^1 + 1 = 6 Then I rewrote it to 5^2(n+1)1 > (25)5^2n + 1 and then I kinda got stuck lol.. 
March 7th, 2010, 09:07 AM  #4 
Senior Member Joined: Apr 2008 Posts: 435 Thanks: 0  Re: mathematic induction
You're pretty much there. I refer to two things: First, if a divides the product bc, but the gcd(a,b) = 1, what do we know about a and c? Second, what does your inductive hypothesis state? And how do we use that? For any proof by induction, we must use our hypothesis in some form or fashion. Is that clear enough? If not, I would recommend writing out your inductive hypothesis explicitly, and see if you can come up with something where it becomes useful. (easier than it sounds) 
March 7th, 2010, 01:29 PM  #5 
Global Moderator Joined: May 2007 Posts: 6,806 Thanks: 716  Re: mathematic induction
5^(2n+1) +1=25[5^(2n1)] +1=25[5^(2n1)+1] 24. [5^(2n1)+1] is divisible by 6 (induction hypothesis). 24 is divisible by 6. Result is divisible by 6. 

Tags 
induction, mathematic 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Is this mathematic logic statement is correct?  danoc93  Applied Math  16  October 2nd, 2013 03:47 PM 
Simple Mathematic yet hard  maple_leaf  Elementary Math  9  May 25th, 2013 06:41 AM 
Mathematic International Journal  Monox D. IFly  Academic Guidance  0  February 24th, 2011 10:49 PM 
Is Mathematic something you can call static or dynamic!  lulzimfazlija  Algebra  2  December 31st, 1969 04:00 PM 
mathematic induction  medos  Applied Math  3  December 31st, 1969 04:00 PM 