(adsbygoogle = window.adsbygoogle || []).push({}); I need SERIOUS HELP...integration by parts!!!

1. The problem statement, all variables and given/known data

Integrate: x^3*e^x

2. Relevant equations

3. The attempt at a solution

I have the answer in my book but I am not understanding why you have to repeat the integration 3 times...

1.) dv = e^x dx

v = e^x

u = x^3

du = 3x^2

S=integral sign lol

S u*dv = uv - S v*du

S x^3*e^3 = x^3*e^x - S 3x^2*e^x dx

And now I have to do this 2 more times but I don't understand why and how I am supposed to know to do that?

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# Homework Help: I need SERIOUS HELP integration by parts

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