how do you integrate (3x^4)(e^(-3x))

Question

myininaya · Answer

do integration by parts

anonymous · Answer

a nice annoying integral that requires you to integrate by parts 4 times!

myininaya · Answer

lol yes they can be pretty annoying

anonymous · Answer

glad i don't have to do it, but if it was me i would cheat. 
(3x^4)(e^(-3x))
and click on "show steps" to see all the work

myininaya · Answer

amistre likes to use a table for this

anonymous · Answer

http://www.wolframalpha.com/input/?i=%283x^4%29%28e^%28-3x%29%29

anonymous · Answer

oh right like in "stand and deliver"

myininaya · Answer

3x^4                   e^{-3x}

12x^3                   -1/3 *e^{-3x}

36x^2                  1/9 *e^{-3x}

72x                       -1/27* e^{-3x}

72                          1/81 *e^{-3x}

0                            -1/243 *e^{-3x}

myininaya · Answer

we do have to alternate signs

myininaya · Answer

3x^4                  

12x^3       +        -1/3 *e^{-3x}

36x^2       -            1/9 *e^{-3x}

72x           +          -1/27* e^{-3x}

72            -            1/81 *e^{-3x}

                             -1/243 *e^{-3x}