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Hey mathematics students...

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... am I the only one that hates integration by parts?

 

I have been dealing with it for ~5 years now, and it still gives me grief.

 

Rob.

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Integration by parts is cinch. It's partial fractions and trigonometric substitution that gets tricky. What don't you get about it?

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... am I the only one that hates integration by parts?

I'd integrate your parts :p

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... am I the only one that hates integration by parts?

I'd integrate your parts :p

 

 

Thems flirting words!!!

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What did one maths major student say to the other maths major student?

 

Would you like fries with that?

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whats the volume of a pizza where the Radius = z, the hight = a

 

 

 

 

= Pi (Z x Z) A

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Integration by parts is cinch. It's partial fractions and trigonometric substitution that gets tricky. What don't you get about it?

Integration by parts bothers me more than partial fractions strangely enough.

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Why's that? It's just breaking a complex integral into lots of easy derivatives and parts. Do one bit at a time, substitute the values into the formula and voila! It's not even really a process.

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Yes. For me though, vector cuntulus is worse.

Really? I had no trouble with vector calculus.

 

Integration by parts is cinch. It's partial fractions and trigonometric substitution that gets tricky. What don't you get about it?

Oh, I get it. When I come accross it on an exam I can bring it back to mind by doing a quick derivation from the differentiation product rule in the margin, it's just that once I figure out what I'm meant to be doing I tend to have a hell of a time identifying the two appropriate functions of (variable).

 

I've now, 4/5 years after I first learnt of IbP decided that the way to tackle it; "I get to integrate one function, and differentitate the other, which do I want for which."

 

Of course, after that, there's a bucketload of tricky algebra that can follow - just begging me to make mistakes. The integral of t^2*e(-t) is one I particularly hate.

 

I've never had any trouble with partial fractions, but I do agree with trig stuff.

 

... am I the only one that hates integration by parts?

I'd integrate your parts :p

 

Oh baby, you'd love the area under my curves, wouldn't you?

 

What did one maths major student say to the other maths major student?

 

Would you like fries with that?

I'm not a maths major :P

 

Rob.

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I had some of the worst troubles with integrals in my class until I realised that I was overthinking things too much. Plus, lots and lots of examples make a huge difference.

t^2*e^(-t) dt

-Assuming you meant e^(-t) as you wouldn't even need intergration by parts to do e*(-t)?

 

let u = t^2

let dv = e^(-t) dt

 

now, du = 2t dt

and v, or the integrand of dv is simply -e^(-t) again but with a negative.

 

Plug that into the formula and => u*v - Integral[v*du] = t^2*-e^(-t) - Integral[ (e^(-t)*2t dt]

 

You would have to repeat that process for the integral at the end until the 2t fell out.

 

And thank geeks for WolframAlpha: http://www4d.wolframalpha.com/Calculate/MS...w=411&h=346

 

Let me know if you want a hand with this stuff, don't mind talking you through some of it.

 

 

edit: On a side note, where you may be getting confused (and where I did too) is when your thinking that the integral you're working out has 3 parts. It doesn't, integration by parts as far as I'm aware only works for 2 variables or elements. So you will never have Integral[tuv dv] it just doesn't work. Knowing that, you can just lump one of the expressions as u and the other as dv in all cases.

Edited by Necessity

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I had some of the worst troubles with integrals in my class until I realised that I was overthinking things too much. Plus, lots and lots of examples make a huge difference.

t^2*e^(-t) dt

My bad, didn't proof read my post.

 

I have absolutely no idea why you think I can't do it, though :P Read the OP, I said I hate it and that it gives me grief.

 

Rob.

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Well one would assume that because it gives you grief you have trouble with it :P

I do have trouble with it. But I can do it, heh.

 

Or, at the verily least, my trouble with it isn't going to be solved by you walking me through an example I've done heaps of time before :P

 

[edit]: I do appreciate you trying to help out, though, just in this case it wasn't required. But hey, know anything about probability through the eyes of sigma-algebra?`

 

 

Rob.

Edited by robzy

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whats the volume of a pizza where the Radius = z, the hight = a

V= a( Pi(z^2))

 

:p

 

hey, I stole it from Beauty and the geek Australia season 2 promo adds.

 

were breaking the rules is a way of life.

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Sorry Necessity, I really didn't mean to be rude. But no one likes it when the other wrongly assumes they don't know something, as it makes them feel patronised when it gets explained to them.

 

I should echo my, honest, sentiments from above on: Good on you for trying to help someone out. Shame on me for taking it so personally :P

 

Rob.

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Robzy it's OK! I'm not going to have a meltdown over this :P

 

Understand being patronised, didn't mean it as such. I guess all those jokes just led me to assume a certain lack of intellect :P jks

 

Glad you understand it then. Funny you bring it up right during uni exam period? You currently at uni?

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Robzy it's OK! I'm not going to have a meltdown over this :P

Heh, I figured, just didn't want to be rude.

 

Understand being patronised, didn't mean it as such. I guess all those jokes just led me to assume a certain lack of intellect :P jks

 

Glad you understand it then. Funny you bring it up right during uni exam period? You currently at uni?

I am actually, currently a few years into actuarial study (with a finance major before that). And yes, it was relevant to some exam-period revision I was doing :P Are you studying? Why do you know this stuff?

 

Rob.

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One of my lecturers told us not to look at it as a whole equation but rather parts of a puzzle instead. So basically, try and simplify everything so that you can do one coherent step at a time. And don't rush things as I do a lot and I end up with equations that doesn't really make sense. At least this is better than proving theorems... >>

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Currently doing a physics major so maths is a given. Finance hey? whats it like? I was going to enrol in a combined physics/economics at the start of next year as I've got no idea what a physics degree can get you, doing it out of pure fascination of the universe :P but finance was another option... recommended?

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Currently doing a physics major so maths is a given. Finance hey? whats it like? I was going to enrol in a combined physics/economics at the start of next year as I've got no idea what a physics degree can get you, doing it out of pure fascination of the universe :P but finance was another option... recommended?

It gets my thumbs up, but I'm somewhat biased :P

 

It's funny, finance - especially when you mix in some economics with it - is also all about how the world works. Or, at least, it is in my eyes. It's kind of like ultra-applied psychology, seeing how a bunch of free agents in a society interact, and shuffle around risk/reward.

 

Rob.

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I am actually, currently a few years into actuarial study (with a finance major before that). And yes, it was relevant to some exam-period revision I was doing :P Are you studying? Why do you know this stuff?

 

Rob.

bwahahahaha....

 

when my wife innocently asked a good friend of ours (who is a boutique banker) what an actuary is, his definition was "actuaries are people who find accounting too exciting"

 

good luck with the exams however

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Haha, bingo scruffy1. That's my second favourite actuarial joke. And thanks for the wishes :) I'll need them.

 

Rob.

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