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!

Simple factoring question

  1. Jan 23, 2009 #1
    1. The problem statement, all variables and given/known data

    can u factor x2+4
    and cant seem to remember the the difference of cubes and isn't there another special cubed theorem.

    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jan 23, 2009 #2

    rock.freak667

    User Avatar
    Homework Helper

    It can be factored but it won't be factored with real numbers. You'd need to introduce the imaginary constant,i, such that i2=-1 and use that to factor.
     
  4. Jan 23, 2009 #3

    Mark44

    Staff: Mentor

    x2 + 4 = (x + 2i)(x - 2i), where i is the imaginary unit rock.freak667 mentioned.
    Here are the sum and difference of cubes formulas:
    x3 + a3 = (x + a)(x2 - ax + a2)
    x3 - a3 = (x - a)(x2 + ax + a2)
     
  5. Jan 23, 2009 #4
    thanks, so i have another question if someone can help me.

    lim x3-62+11x-6
    x->-1 x3-4x2-19x +14
    i cant seem how to factor the top out if i even need to do that or the bottom
     
  6. Jan 23, 2009 #5

    rock.freak667

    User Avatar
    Homework Helper

    Why would you need to factor it? Did you evaluate it at x=-1? Was it in the indeterminate form 0/0?
     
  7. Jan 23, 2009 #6

    Fermat

    User Avatar
    Homework Helper

    If the numerator, or denominator, goes to zero when x = 1, then (x-1) is a factor.

    You can factor it out by dividing (x-1) into the numerator, say, in the style of long-division.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Simple factoring question
  1. Factoring question (Replies: 17)

  2. Factoring question (Replies: 4)

  3. Factor question (Replies: 7)

Loading...