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Homework Help: Simple Laplace trasfrom

  1. Nov 18, 2012 #1
    1. The problem statement, all variables and given/known data
    L[cos2at]

    I know that L[cost] = s/(s2+bs)

    I know that cos2at can also be written as 1/2(1+cos2at)

    and so I then got the L[1/2]+1/2L[cos2at)]

    Which gave me s/(s2+(2a)2)

    However this is not correct, there was a + 2at term on the numerator as well.

    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Nov 18, 2012 #2

    rock.freak667

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    Homework Helper

    L[tn] = n!/sn+1

    For L[1/2], n= 0 so you should get 1/2s as that transform.
     
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