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!

Help with 2 problems!

  1. Mar 22, 2010 #1
    1. The problem statement, all variables and given/known data

    1) Find the General Solution to:
    (D3 - D2 + D - I)[y] = t5 + 1

    2) Prove or disprove that there are two constants A and B such that:
    t2D - tD - 8I = (tD + AI)(tD + BI)



    2. Relevant equations


    3. The attempt at a solution

    1) I can't figure out how to attempt this one. Doesn't make sense to me.
    2) I should FOIL out the RHS of the equation, but I did that on paper and it didn't make too much sense to me.
     
  2. jcsd
  3. Mar 22, 2010 #2

    gabbagabbahey

    User Avatar
    Homework Helper
    Gold Member

    There are two methods that immediately come to mind:

    (1)Use the method of Undetermined Coefficients

    (2)Use the annihilator method

    Show us what you've got, and keep in mind that to calculate something like [itex]D(tD)[/itex] you need to use the product rule.
     
  4. Mar 23, 2010 #3
    There was a typo in #2:

    2) Prove or disprove that there are two constants A and B such that:
    t2D2 - tD - 8I = (tD + AI)(tD + BI)
     
  5. Mar 24, 2010 #4

    Mark44

    Staff: Mentor

    There are solutions for A and B if you permit complex solutions.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook