Help with this solving this equation !!!!!

Discussion in 'Math' started by kingmort, Mar 20, 2011.

  1. kingmort

    Thread Starter New Member

    Mar 4, 2011
    4
    0
    Please help me to prove that

    X" + ( a^2 )X = 0 where X= Asin(ax) + Bcos(ax)


    Cause I got a different expression with an exponential and when I use maclaurin to approximate my expression and the supposed function , I found them to be different .
    Help would be greatly appreciated !!!!
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    This might help


    X=Asin(ax)+Bcos(ax)

    X'=aAcos(ax)-aBsin(ax)

    X"=-a^2Asin(ax)-a^2Bcos(ax)

    a^2X=a^2Asin(ax)+a^2Bcos(ax)

    X"+a^2X=?
     
    SaraSa likes this.
  3. kingmort

    Thread Starter New Member

    Mar 4, 2011
    4
    0
    hi , thanks for the reply , however would you mind trying to solve the differential equation above ? i m trying to see if i did the solved it wrongly ... thanks !!!
     
  4. kingmort

    Thread Starter New Member

    Mar 4, 2011
    4
    0
    i mean solved it wrongly
     
  5. kingmort

    Thread Starter New Member

    Mar 4, 2011
    4
    0
    Solved it already ... Need not bother about this thread
     
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