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!

Polynomial Division puzzler(well to me anyway :P )

  1. Feb 20, 2006 #1
    O.K I factored and reduced an equation I am doing down to (s+5t)/(t-s)

    I could not figure it out so I went to webmath and used a calculator to find out the answer so I could reverse solve the problem. The answer is 1 according to webmath. Any hints on how to get started on this becuase I do not see how you can get rid of the 5?:yuck:
  2. jcsd
  3. Feb 20, 2006 #2
    If it is an equation, what is the remaining part of the equation? How did you factor what you have so far?
  4. Feb 20, 2006 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There's a very easy way to prove (s + 5t) / (t - s) is not identically equal to 1. (I'll give you time to figure this one out -- and I advise doing so, it's a widely useful but overlooked technique)

    Have you tried going through the problem a second time? I find that I rarely make the same mistake twice. So when I'm not completely confident in my arithmetic, I will often do the same problem twice from scratch (and in different ways, if possible) to check myself. If I get a mismatch, I can often track down exactly what I did wrong.

    But finally, I can't possibly figure out what you've done wrong unless you showed your work. :smile:
  5. Feb 20, 2006 #4
    O.k. Here goes. The equation is
    20s^2+9st+t^2 2s^2-7st+3t^2 5s^2+6st+t^2
    -------------- * --------------- * --------------
    5s^2-14st-3t^2 t^2+3st-4s^2 10s^2-3st-t^2

    factored out to

    (5s+t)(4s+t) (2s-t)(s-3t) (5s+t)(s+5t)
    (5s+t)(s-3t) (t-s)(t+4s) (5s+t)(2s-t)

    reduced to
    from this point I am stuck.
  6. Feb 20, 2006 #5
    The numerator in your last fraction: [itex]5s^2+6st+t^2\neq(5s+t)(s+5t)[/itex].
  7. Feb 20, 2006 #6
    I re did the equation and ended up with (s+t)/(s-t). Thanks everyone.
  8. Feb 20, 2006 #7


    User Avatar
    Staff Emeritus
    Science Advisor

    So far you haven't shown us any equation. An equation has to have a "= " somewhere in it!

    And (s+t)/(s-t) still isn't equal to 1!
  9. Feb 20, 2006 #8
    Sorry It was perform the indicated operation. Not solve the equation. Honestly i did not know an equation had to have a = . The instructor at the community college I am going to never spent any time on terms.
  10. Feb 20, 2006 #9
    As for the 1 thing. I think the calculator on webmath is messed up. It said (s+t)/(s-t) =1 But my calculator says in doing so you would have to divide by zero which cannot be done.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Polynomial Division puzzler(well to me anyway :P )
  1. Polynomial Division (Replies: 3)

  2. Polynomial division (Replies: 2)

  3. Polynomial Division (Replies: 16)