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kirbykirby
Group Title
Integral! (related to gamma function maybe?)
\[\int\limits_{0}^{X}\frac{\lambda^3}{2}t^2e^{\lambda t}dt
 one year ago
 one year ago
kirbykirby Group Title
Integral! (related to gamma function maybe?) \[\int\limits_{0}^{X}\frac{\lambda^3}{2}t^2e^{\lambda t}dt
 one year ago
 one year ago

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kirbykirby Group TitleBest ResponseYou've already chosen the best response.0
Here it is: \[\int\limits_{0}^{X}\frac{\lambda^3}{2}t^2e^{\lambda t}dt\] I tried doing this trying to relate it to a gamma function but myupper bound is not infinity :S: \[=\frac{\lambda^3}{2}\int\limits_{0}^{X}t^2e^{\lambda t}dt\] \[Let : u=\lambda t =>t=u/t\]\[So: du=\lambda dt\]\[Bounds: u=0=>t=0 ; u=x=>t=x/\lambda\] \[\frac{\lambda^2}{2}\int\limits_{0}^{X/\lambda}(\frac{u}{\lambda})^2e^{u}du\]\[=\frac{1}{2}\int\limits_{0}^{X/\lambda}u^{31}e^{u}du\]
 one year ago

Outkast3r09 Group TitleBest ResponseYou've already chosen the best response.1
why do you not just use tabular method
 one year ago

kirbykirby Group TitleBest ResponseYou've already chosen the best response.0
What's that?
 one year ago

Outkast3r09 Group TitleBest ResponseYou've already chosen the best response.1
it's a special type of by parts.. you can do by parts also
 one year ago

Outkast3r09 Group TitleBest ResponseYou've already chosen the best response.1
dw:1358916012425:dw
 one year ago

Outkast3r09 Group TitleBest ResponseYou've already chosen the best response.1
dw:1358916166540:dw
 one year ago

Outkast3r09 Group TitleBest ResponseYou've already chosen the best response.1
\[\int t^2e^{yt}=\frac{t^2e^{yt}}{y}\frac{2te^{yt}}{y^2}\frac{2e^{yt}}{y^3}+c\]
 one year ago

kirbykirby Group TitleBest ResponseYou've already chosen the best response.0
Hmm interesting o_o!! As I was trying to do integration by parts, I realized I have to do it twice. Is this method related to doing int. by parts multiple times?
 one year ago

Outkast3r09 Group TitleBest ResponseYou've already chosen the best response.1
http://www.wolframalpha.com/input/?i=integral+of+t%5E2e%5E%7Byt%7D same answer as mine only simplified and yes Tabular method is when you have something of this sort \[\int t^nf(t)dt\] you take the derivatives of the t to thepower until you get to zero giving them alternating signs and integrate the f(t) one more time than how many it takes the t power function goes to zero
 one year ago

Outkast3r09 Group TitleBest ResponseYou've already chosen the best response.1
look up tabular method for a derivation of this
 one year ago

kirbykirby Group TitleBest ResponseYou've already chosen the best response.0
Oh wow this is quite neat !! :) thank you so much
 one year ago

kirbykirby Group TitleBest ResponseYou've already chosen the best response.0
I can't believe they never taught this technique..
 one year ago
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