
Computer Science Computer Science Forum 
 LinkBack  Thread Tools  Display Modes 
February 5th, 2012, 08:21 PM  #1 
Newbie Joined: Oct 2011 Posts: 22 Thanks: 0  Mathematical Induction technicality help wanted!
Hey anyone can help me with a little confusion here: Prove that 0+1+...+n = n(n+1)/2 I did the base case, where P(0) is 0 on the left and right hand sides. I made the inductive hypothesis: ...+k= k(k+1)/2 Then to show P(k+1) is also true: 0+1+...+k +(k+1) = k+1((k+1)+1)/2 Using the i.h. we plug into this and get: k(k+1)/2 + (k+1) = k+1(k+2)/2 I left the right hand side alone since that's the desired result we need on the left hand side. However the left hand side I got lost. I tried distributing: k^2+k/2 + k+1 but that doesn't equal the right hand side! Unless I'm overlooking things, or just need to see a different algebraic manipulation here. Thanks in advance to those who help me! 
February 5th, 2012, 08:31 PM  #2 
Global Moderator Joined: Nov 2009 From: Northwest Arkansas Posts: 2,767 Thanks: 5  Re: Mathematical Induction technicality help wanted!
(k^2 + k)/2 + k + 1 = (k^2 + k)/2 + 2(k + 1)/2 = [k^2 + k + 2k + 2]/2 = ... The right hand side. You need a common denominator of 2 on the LHS in order to combine into one fraction. 

Tags 
induction, mathematical, technicality, wanted 
Search tags for this page 
Click on a term to search for related topics.

Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Mathematical Induction  matqkks  Algebra  8  June 28th, 2013 06:17 AM 
Mathematical Induction help please.  firstsin  Algebra  7  January 28th, 2012 12:09 PM 
Help with mathematical induction  Sunde  Algebra  14  August 3rd, 2011 05:10 PM 
mathematical induction  supercali  Calculus  0  November 2nd, 2007 01:52 AM 
Mathematical Induction help please.  firstsin  Abstract Algebra  0  December 31st, 1969 04:00 PM 