Recent content by PhantomOort
-
P
Undergrad Name for integration by parts shortcut
It's for integrals like \int x sin(x) dx, which are usually done by parts. Not that this is super hard, but with the shortcut, \lambda=0, \mu = -1, and the result is sin(x)-xcos(x) and we're done. PS, my apologies to any readers put off by the formatting. I'm utterly unfamiliar with this...- PhantomOort
- Post #7
- Forum: Calculus
-
P
Undergrad Name for integration by parts shortcut
Damn, I could have done that! I need to stop being so lazy. Thanks.- PhantomOort
- Post #6
- Forum: Calculus
-
P
Undergrad Name for integration by parts shortcut
Yes, both \lambda and \mu are numbers. Obviously this only works in cases where they exist, such as for exponentials, trig functions, or x. But these make up a great many common integrals, so it's a pretty good shortcut.- PhantomOort
- Post #3
- Forum: Calculus
-
P
Undergrad Name for integration by parts shortcut
Hi all. I've recently learned a shortcut for integration by parts, but don't know what it's called or where it comes from. The trick is to find \lambda such that f'' = \lambda f and \mu such that g'' = \mu g, providing both are constants and \lambda\neq\mu. Then \intf(x)g(x)dx =...- PhantomOort
- Thread
- Integration Integration by parts parts
- Replies: 6
- Forum: Calculus
-
P
The Most Hilarious Halloween Dog Costume Ever view
I'm pretty sure this dog is less happy.- PhantomOort
- Post #2
- Forum: Fun, Photos and Games
-
P
On the issue of kids not pursuing engineering/science/math these days
I only recently found this thread (and this site) and a few questions pop into my mind as I read. Well, actually just one. If we replaced the word "math" in the last eight pages with words or phrases like "singing", "foreign language acquisition", "painting", "(good) creative writing", or...- PhantomOort
- Post #118
- Forum: General Engineering
-
P
How can the drivers determine who has the right of way?
It's a moot point. If you see that three other drivers are going to reach the stop at the same time you do, just slow down or speed up to make sure the problem doesn't arise. That's what I do. Like I can't wait a few more seconds to get where I'm going?- PhantomOort
- Post #12
- Forum: General Discussion
-
P
Graduate Stuff I always wondered about astrophysics
35. If the monoliths have mass then they have gravity. Thus, with enough of them the added gravitational force will be enough to compress the hydrogen and initiate fusion, just as happens in the real universe.- PhantomOort
- Post #15
- Forum: Astronomy and Astrophysics