Math Is Fun Forum
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#1 Re: Help Me ! » Integral question » 2008-03-29 12:44:08
It's a classic question, tha answer is
#2 Re: Help Me ! » How to do this integral? » 2008-03-29 12:27:15
Let's perform a double integration solution:
The rest follows. Easy, huh ¿?
#3 Re: Help Me ! » Iterated Integral, order reversal » 2008-03-29 12:02:22
Have you sketched the region where the integral is taken? That'd help.
#4 Re: Exercises » Evaluate Integral » 2008-01-25 13:38:50
Hola, jaja
Ya está resuelta en aquél foro. (I'm not gonna post the URL for not makin' SPAM.)
Tony: you should be patient, post your problems in one forum first, if you see that it's not solved, try with another ones.
#5 Re: Help Me ! » simplify » 2007-12-20 02:31:55
You'll get quickly the desired.
#6 Re: Puzzles and Games » prove » 2007-12-17 11:58:16
I couldnt believe that nobody saw that the best way to solve the equation is not to expand everything out into a mess but to exploit the symmetry of the equation and use a substitution in this case the equation is symmetrical about r−2, so the substitution is R = r−2. I had to register on their forum just to tell them how it should be done.
Don't worry, there're smart guys.
In any case, I hadn't seen such thread 
#7 Re: Puzzles and Games » prove » 2007-12-17 04:00:12
Of course you should see something wrong with that.
Do you know www.mathhelpforum.com ? He's actually posting the same questions there and takin' solutions from another posters to show them right here.
Well, whatever.
#8 Re: Puzzles and Games » prove » 2007-12-17 03:40:29
Dear perash, you recently posted the same problem on MHF and you received an answer, did you see it?
#9 Re: Help Me ! » Improper integrals » 2007-12-11 13:25:57
Okay, I've got it.
And rewrite
The rest follows constructin' a double integral.
#10 Re: Help Me ! » Improper integrals » 2007-12-01 14:20:39
It's similar to #1. Use the following parameter:
From there construct a double integral, the rest follows.
--
As for the third one, let me think it a little bit, looks like hard.
#11 Re: Help Me ! » Improper integrals » 2007-12-01 06:01:33
Beautiful problems!
Evaluate
Construct a double integral and reverse the integration order,
Now
And
#12 Re: Help Me ! » lim » 2007-12-01 01:48:35
where as by Taylor's theorem.Thus,
.
You stole this from a guy of another forum, what a shame.
You didn't even change any word.
#13 Re: Help Me ! » Integral with arctan » 2007-11-24 02:28:36
Let
Consider
Since
You may go on from there.
--
If you know Frullani's Integral, you can get the result directly.
#14 Re: Maths Is Fun - Suggestions and Comments » "Math is Fun" in Spanish? » 2007-11-24 02:05:03
Once I get it off the ground I think there may be a lot of Spanish-speaking visitors directed to this forum.
Spanish is my mother language ^^
By the way, do you like "disfrutalasmatematicas.com" ... ?
I like "disfrutalasmates.com".
Short & "mates" sounds better than "matemáticas".
#15 Re: Maths Is Fun - Suggestions and Comments » "Math is Fun" in Spanish? » 2007-11-23 15:28:24
Just wonderin'.... why instead creating a domain you create, here, a spanish section?
#16 Re: Maths Is Fun - Suggestions and Comments » eqnarray* » 2007-11-23 09:13:16
Thank you.
Also, the command \implies does not work. It's the same as \Longrightarrow.
#17 Re: Help Me ! » Improper one » 2007-11-23 08:44:52
Evaluate
The integral can be rewritten as
Substitute
#18 Re: Help Me ! » Another integral » 2007-11-23 08:34:10
Evaluate
Substitute
Make another substitution defined by
#19 Re: Help Me ! » Integral again » 2007-11-23 08:17:31
Yeah, it's a little application about a formula that I recently proved.
Evaluate
Another attempt it is to define the following integral
Since
Or substitute
and from there construct a double integral to tackle the problem.
Or Frullani's Integral may be useful.
#20 Re: Maths Is Fun - Suggestions and Comments » eqnarray* » 2007-11-23 08:05:41
No, I mean
This looks nice, but when using \frac, there's not enough space.
That's why eqnarray environment is perfect for alignment.
#21 Maths Is Fun - Suggestions and Comments » eqnarray* » 2007-11-23 05:19:28
- Krizalid
- Replies: 7
Could the Admin. activate the eqnarray environment ¿?
\begin{eqnarray*}
\end{eqnarray*}
That'd be nice.
#22 Re: Help Me ! » Double Integral » 2007-11-23 04:53:23
Id suggest changing to polar co-ordinates.
To do that, split the original square into two triangles:
#23 Re: Maths Is Fun - Suggestions and Comments » "Math is Fun" in Spanish? » 2007-11-22 13:45:36
Aha, you like: www.disfrutalasmates.com?
#24 Re: Maths Is Fun - Suggestions and Comments » "Math is Fun" in Spanish? » 2007-11-22 13:30:52
I am thinking it would be good to translate some of the mathsisfun.com website to Spanish, but what would "Math is Fun" be in Spanish
"Matematicas es divertida" ... ? Not a good domain name: matematicasesdivertida.com
Any Ideas?
Ohh!!
That'd be nice!
You like spanish ¿?
--
I think we can call it "Mate es entrete".
"Entrete" means "Fun", actually, the complete spanish word is "Entretenida", but it is a little large for the domain name.
#25 Re: Maths Is Fun - Suggestions and Comments » i got some ideas for some new smilies » 2007-11-22 13:27:39
I have lots of nice smileys, if you want them, I can show them to you.