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!

Yet another simple factorizing question

  1. Mar 1, 2008 #1
    [SOLVED] yet another simple factorizing question..

    I wont re-write the full question, just one line on the numerator:

    from the solutions, (a + 1)^2 − (a − 1)^2 factorizes to:

    ((a + 1) − (a − 1))((a + 1) + (a − 1))

    I can see that this is just another form of:

    (a + 1)(a + 1) - (a - 1)(a - 1)

    but why is the former, and not the later used?

    does it make it easier to go to the next step to complete factorization process?

    If so please explain why.
  2. jcsd
  3. Mar 1, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Well, it's going to depend on what the question asks next!
  4. Mar 1, 2008 #3
    the solution continues on like this:

    = (a + 1 − a + 1)(a + 1 + a − 1)

    = 4a

    (the question is to factorize.. i dont know what you mean by "what does it ask next")
    Last edited: Mar 1, 2008
  5. Mar 1, 2008 #4


    User Avatar
    Staff Emeritus
    Science Advisor

    Ok, I think I get what you mean now. Well, your first expression is in the form x^2-y^2, which is a difference of two squares. We know that the factorisation of a difference of two squares is (x+y)(x-y); it just turns out that in this case the expression simplifies further.

    The second expression you give in your first post is not a factorisation of (a+1)^2-(a-1)^2, but is an expansion.
  6. Mar 1, 2008 #5
    thank you, understood
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Yet another simple factorizing question