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paerabol
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working on a laplace transform and it'd be a breeze if i could remember how to freaking integrate (it's been a while).

according to sources i should be able to use integration by parts to solve this, but this is what I keep coming up with



either way i'm left with essentially the same thing i started with behind the integral.

am i doing it wrong or should i use a different method? and yes, i need to solve this using the Laplace definition as opposed to looking at tables

12/15/2010 5:49:18 PM

lewisje
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Use the second method twice, then you'll have an equation that can be re-written as
F(s)=G(s)-H(s)F(s)
for some G(s) and H(s)
and be sure to evaluate uv at infin. and 0 and then take their difference, because this is a definite integral, so that term outside the integral after the first use of the second method should be 0.

If you still have trouble I'll tell you more.

12/15/2010 8:29:21 PM

paerabol
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that was it, thanks...just didn't grasp that the cyclical nature was going to be my friend after all, if i'd quit being lazy and chugged through it i'd have figured it out

thanks for your help i really do appreciate it



confirmed by the tables woop woop

12/15/2010 9:36:10 PM

lewisje
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Sometimes you really don't get anywhere by repeatedly taking integration by parts

but sometimes you do

this integral looks like something you should have mastered back in Calculus II

12/17/2010 2:09:58 AM

paerabol
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Wasn't so much the integration itself as it was the utility thereof that lost me. In any case this is my first semester back in 4 years and I guess haven't quite scrubbed off all the rust just yet

12/17/2010 2:27:13 AM

lewisje
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oh ok

I hope you have re-discovered the fun of symbolic manipulation

12/17/2010 8:32:18 PM

ApexDave
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If you need a refresher just watch Remember the Titans. Its football season so odds are it'll be back on basic cable sometime in the next week.

12/18/2010 9:56:50 PM

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