Doing integration by parts...

[randomlinh]

my roommate claims there is some kind of acronym or shortcut in order to help figure out which part to use for u and/or dv.

Now, i don't have a clue to what he's talkin about.. but anyone here have any ideas?

 

[LAUST]

I think thats Talk-Fu.. he's using big words just to scare you

 

[Shmorq]

I remember there being one too (similar to PAMDAS or something like that for basic math). I can't remember it though...:frown:

 

[Soccer55]

The acronym is LIPET

L = logs (ln)
I = inverse functions
P = polynomials
E = exponentials
T = trig functions

-Tom

 

[randomlinh]

is that for deciding which one is u?

 

[Soccer55]

I believe so.....like if you have a log function and a polynomial function, the log would become "u" because it is left most in the acronym.....if they're the same (ie: 2 polynomials) you get to pick. I'm not 100% positive that this is correct (it could be that it's choosing dv) because it's been a year since I did any integration by parts, but I'm almost positive this is correct. Try it out with an easy problem and see which way works to be certain.

-Tom

 

[randomlinh]

it only makes sense to me for it to be U cause if ln = dv, taking the integral of it is a pain to do.

 

[Unsickle]

Ahh, but now do you know the best technique? It's called rapid repeated integration by parts. I used it to smoke a few midterms in my day (learned in high school, wasn't taught in college).

 

[randomlinh]

would you mind sharin?