Interesting problem (not very difficult) - Singapore Forums by SGClub.com
Singapore Forums by SGClub.com
Sitemap Contact Us FAQ Singapore Forums by SGClub.com
Home Photos Member List Register Mark Forums Read  
Go Back Home > Lifestyle > School Life > Math Help » Interesting problem (not very difficult)

Why aren't you a member of SGClub.com yet??

» Join 130,000+ other members in chatting.
» Make lots of new friends here.
» Keep up-to-date with current events.
» Participate in Club outings.
» Download lots of Free Stuff!

Registration just takes 2mins and is absolutely free so join our community today!

I Want to Choose my Own Personal Nickname Now!


Reply
 
LinkBack Thread Tools Display Modes
Old 8th February 2012, 10:58 PM   #1 (permalink)
Experienced SGClubber
whitecorp is a glorious beacon of lightwhitecorp is a glorious beacon of lightwhitecorp is a glorious beacon of light

 
whitecorp's Avatar
 
Posts: 2,404
Join Date: Jul 2009
Likes: 0
Liked 211 Times in 174 Posts
Gender:

Interesting problem (not very difficult)

By not using the fact that 2^12 -1 =4095,

Find the largest prime factor of 2^12 -1.

This is an American maths competition question modified by me. Peace.

Sponsors:

Last edited by whitecorp; 8th February 2012 at 11:01 PM.
whitecorp is offline  
Add to whitecorp's Reputation Reply With Quote
Old 8th February 2012, 11:03 PM   #2 (permalink)
By2
V.l.P SGClubber
By2 is just really niceBy2 is just really nice

 
By2's Avatar
 
Posts: 6,125
Join Date: Nov 2009
Likes: 2
Liked 89 Times in 67 Posts
Gender:

Re: Interesting problem (not very difficult)

i've been failing maths since 13 .
but i think prime factor is the

l_____
l_____
l_____
l_____

if i rmb correctly xD

By2 is offline   Add to By2's Reputation Reply With Quote
Old 12th February 2012, 02:08 PM   #3 (permalink)
Experienced SGClubber
whitecorp is a glorious beacon of lightwhitecorp is a glorious beacon of lightwhitecorp is a glorious beacon of light

 
whitecorp's Avatar
 
Posts: 2,404
Join Date: Jul 2009
Likes: 0
Liked 211 Times in 174 Posts
Gender:

Re: Interesting problem (not very difficult)

Just clearing this up in case anyone is interested:

2^12 -1 = (2^6 +1 )( 2^6 -1)
= (2^6 +1 ) (2^3 +1 ) (2^3 -1 )
= (65)(9)(7)
= 13*5*3*3*7

Hence, the largest required prime factor is 13. (shown)

Hope it helps. Peace.

whitecorp is offline   Add to whitecorp's Reputation Reply With Quote
Members who Liked this post by whitecorp:
workingtoohard (13th February 2012)
Old 19th February 2012, 12:45 AM   #4 (permalink)
Addicted SGClubber
Icystrike is on a distinguished road

 
Icystrike's Avatar
 
Posts: 362
Join Date: Jun 2007
Likes: 1
Liked 2 Times in 2 Posts
Gender:

Re: Interesting problem (not very difficult)

Originally Posted by whitecorp View Post
Just clearing this up in case anyone is interested:

2^12 -1 = (2^6 +1 )( 2^6 -1)
= (2^6 +1 ) (2^3 +1 ) (2^3 -1 )
= (65)(9)(7)
= 13*5*3*3*7

Hence, the largest required prime factor is 13. (shown)

Hope it helps. Peace.
If the question is something like 2^30-1

I guess it will be make effective to use the method to evaluate 2^15+1 and find the prime factor.

Icystrike is offline   Add to Icystrike's Reputation Reply With Quote
Reply

Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Difficult to get into SAF MDC? GuessMyName National Service Forum 1 25th October 2011 08:23 PM
It's just too difficult christmas_ International & Singapore News 13 5th September 2010 10:03 PM
Difficult colleagues Lake_paint Workplace and Business Forum 10 23rd September 2009 04:54 PM
How come it's so difficult getting across to teens? lilo SGClub Cafe 22 26th April 2009 02:15 AM
A Difficult Question Altumangel SGClub Cafe 7 17th May 2008 05:57 PM

» Sponsors
Watch Free Movies Online
Celebrity Gossip
Food Delivery

» Facebook Fans
» What's Going On?
Title, Username, & Date
Ritter Sport chocolate recalled due to undeclared allergen
Aoki Hagane no Arpeggio: Ars Nova
I really hate my mother!!!
Mum's Kitchen Catering and Cherish Delights get licences suspended after nearly 40 people...
Transcend RDF9K2 All-in-One Card Reader
Transcend ESD250C, a portable SSD that’s super classy
Stupid court of appeal gives red light running driver who hit pedestrian 15% discount
How PAP exploited racial differences to impose FASCIST rule over Singapore.
Up to S$7250 of government $ misused for buying each vote in Singapore?
Funky Fields organic vegan spreadable recalled due to 'undisclosed allergen'
100 hawksbill turtles released into the sea after rare hatching on Sentosa
Inspirational Songs
Repost comment.
MOH, SFA investigating after 18 typhoid fever cases in 3 weeks
By militarily invading Hong Kong, Xi Jingping is setting in motion, the wheels of nuc
Deng XiaoPing original vision for HKG- China reunification was for the two to unite a
HSA warns against three products
Warning : Blacklist buyer/adopter Alert
512GB Transcend 830S M.2 SSD Review
Poisonous PAPers.
Featured Photos
by marisoljames322
· · ·
Member Galleries
20359 photos
13619 comments
by marisoljames322
· · ·
Member Galleries
20359 photos
13619 comments
by pdsubbu
· · ·
Member Galleries
20359 photos
13619 comments
by Vikas Dhar
· · ·
Photography
35 photos
36 comments
by aaudreygan
· · ·
Guy Photos
1581 photos
946 comments
by aaudreygan
· · ·
Girl Photos
4351 photos
28606 comments
by a8paris
· · ·
Guy Photos
1581 photos
946 comments
by a8paris
· · ·
Guy Photos
1581 photos
946 comments
by aaricia
· · ·
Girl Photos
4351 photos
28606 comments
by aaricia
· · ·
Girl Photos
4351 photos
28606 comments

 

All times are GMT +8. The time now is 09:57 PM.


Powered by vBulletin
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright© 2004-2013 SGClub.com. All rights reserved.