1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Quick help

  1. Oct 25, 2007 #1
    I cant seem to figure out how to simplify this!!!!

    n(n+1)/2 + n+1

    which they were able to get (n+1)(n+2)/2 by simplifying that

    and this

    n(n+1)(2n+6)/6 + (n+1)^2

    and they were able to get (n+1)(n+1+1)(2(n+1)+1)/6 out of this one.

    Any help is greatly appreciated.
     
  2. jcsd
  3. Oct 25, 2007 #2
    Try this: surely you know how to "expand" parenthesis, like this: a(b+c) ---> ab + ac.

    So do this both from the given problem expression, and also from the answer. Like this:
    Problem -----> xxx
    Answer ------> xxx
    And try to get the same "xxx" starting from both ends.

    When you have that, you can walk *forward* the steps from the problem, and then *backward* the steps from the solution:
    Problem ------> xxx -------> Answer.
     
  4. Oct 25, 2007 #3
    ok i did that but for the first one i get

    (n^2 + n)/2 + n + 1

    =

    n^2 + n + n + 1/2

    = n^4 + 1/2

    but this does not equal (n+1)(n+2)/2
     
  5. Oct 25, 2007 #4
    You have only expanded the parenthesis on the initial problem... but have not expanded them yet on the solution. Try expanding (n+1)(n+2)/2.

    And hey! Watch out, the /2 is dividing (n^2 + n), and only those two. Try again the first part.
     
    Last edited: Oct 25, 2007
  6. Oct 25, 2007 #5
    ooo I see I got it.. Thanks for the help!!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Quick help
  1. Quick help! (Replies: 2)

Loading...