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Postby TSchultz » Tue Sep 04, 2007 5:32 am

YES.
y=x^3/3-x^2+2x+C

y''=2x-2
y'=x^2-2x+2
y''+y'=x^2
Last edited by TSchultz on Tue Sep 04, 2007 5:33 am, edited 1 time in total.
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Postby JustcallmeDrago » Tue Sep 04, 2007 5:32 am

gra(p)h, what?
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Postby JustcallmeDrago » Tue Sep 04, 2007 5:35 am

:shock: what does the C do?
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Postby TSchultz » Tue Sep 04, 2007 5:36 am

It's just a random constant that doesn't matter. (It dissapears when you take the derivative of y)
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Postby Ikerous » Tue Sep 04, 2007 5:37 am

TSchultz wrote:YES.
y=x^3/3-x^2+2x+C

y''=2x-2
y'=x^2-2x+2
y''+y'=x^2

Lol nice. What method did you use to solve it?

I probably would've taken y = ax^4 + bx^3 + cx^2 + dx and solved for the constants :P
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Postby JustcallmeDrago » Tue Sep 04, 2007 5:40 am

Sigh, this sucks. I'm here doing college freshman level "world civ" crap while I want to be learning about this stuff! I don't even care about mesopotamia !! :evil: :evil: :evil:

I want to be an engineer!
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Postby TSchultz » Tue Sep 04, 2007 5:41 am

y''+y'=x^2
y'+y=x^3/3
Multiply by e^x
y'e^x+ye^x=x^3/3*e^x
(ye^x)'=e^x*x^3/3
Integrate with IBP
ye^x=e^x(x^3/3-x^2+2x-2)
y=x^3-x^2+2x+C And I suppose +Ce^-x....
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Postby TSchultz » Tue Sep 04, 2007 5:42 am

JustcallmeDrago wrote:Sigh, this sucks. I'm here doing college freshman level "world civ" crap while I want to be learning about this stuff! I don't even care about mesopotamia !! :evil: :evil: :evil:

I want to be an engineer!

That's why I might apply to brown. I can't take all math. I want to go to MIT or Harvard more since they are closer and have better math.

I don't want to think about applying to places untill I have to in a year or two, but my mom is making me.
Last edited by TSchultz on Tue Sep 04, 2007 5:44 am, edited 1 time in total.
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Postby Ikerous » Tue Sep 04, 2007 5:42 am

TSchultz wrote:y''+y'=x^2
y'+y=x^3/3
Multiply by e^x
y'e^x+ye^x=x^3/3*e^x
(ye^x)'=e^x*x^3/3
Integrate with IBP
ye^x=e^x(x^3/3-x^2+2x-2)
y=x^3-x^2+2x+C And I suppose +Ce^-x....

So what you're saying is I probably should've been sober when I went to differential equations class?

What do you wanna major in?
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Postby TSchultz » Tue Sep 04, 2007 5:44 am

Ikerous wrote:
TSchultz wrote:y''+y'=x^2
y'+y=x^3/3
Multiply by e^x
y'e^x+ye^x=x^3/3*e^x
(ye^x)'=e^x*x^3/3
Integrate with IBP
ye^x=e^x(x^3/3-x^2+2x-2)
y=x^3-x^2+2x+C And I suppose +Ce^-x....

So what you're saying is I probably should've been sober when I went to differential equations class?

What do you wanna major in?

I have no clue. /Points to edited post above.
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Postby JustcallmeDrago » Tue Sep 04, 2007 5:47 am

Well, for me: Not history and Not english, or any other language.
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Postby Ikerous » Tue Sep 04, 2007 5:48 am

JustcallmeDrago wrote:Well, for me: Not history and Not english, or any other language.

What kinda engineer would you like to be? I'm an electrical engineering major
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Postby TSchultz » Tue Sep 04, 2007 5:48 am

JustcallmeDrago wrote:Well, for me: Not history and Not english, or any other language.

I agree.
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Postby JustcallmeDrago » Tue Sep 04, 2007 5:49 am

Ikerous wrote: I'm an electrical engineering major


Hell yes! Does that include computerwork too? like gizmos interfacing with computer?

Hmm... and also physics stuff probably. I wonder what made me like physics so much... :wink:

Just read wikipedia: I'm going to be an electronics engineer (smaller stuff than power plants and such).
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Postby JohnnyRoastbeef » Tue Sep 04, 2007 1:51 pm

TSchultz wrote:
JustcallmeDrago wrote:Sigh, this sucks. I'm here doing college freshman level "world civ" crap while I want to be learning about this stuff! I don't even care about mesopotamia !! :evil: :evil: :evil:

I want to be an engineer!

That's why I might apply to brown. I can't take all math. I want to go to MIT or Harvard more since they are closer and have better math.

I don't want to think about applying to places untill I have to in a year or two, but my mom is making me.


Honestly, I know how hard it is to feel like the History and Art classes are worthwhile when you're taking them (I was there), but there is a bright side to it.

1) As an engineer, those are the only classes you get to pick. The majority of your major courses are laid out for you up through senior year. This is your only chance to study things that interest you besides engineering, and you'd be wise to take advantage of it instead of blowing it off as a waste of time.
2) It really helps you to understand why what you're doing is valuable. And it lets you see what's valuable about what other people do. You're studying the math and the physics because you can do it, but that's not something everybody has the mind for. Just like I (at least) didn't have the mind for creative writing.
3) It gives you an edge when watching Jeopardy.

I'm a mechanical engineer by the way.
At long last I have an avatar.
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