I look for good books on solving partial diffrential equations (PDE's) using integral transforms specially Fourier and laplace transforms.
Do you have any recommendations for such books? I don't look for a book concerned with the theory, rather, with the methods itself (a suitable book for a...
Homework Statement
Suppose Y\subset X and X,Y are connected and A,B form separation for X-Y then, Prove that Y\cup A and Y\cup B are connected.
The Attempt at a Solution
I can show easily that at least one of Y\cup A or Y\cup B is connected. but I don't know how to show the...
Sure, I know that a function is continuous if the preimage of an closed set is closed. and a set is closed iff its closure is the set itself. I lately heared that an element x is in the closure of a set if every neighborhood of x intersects the set itself.
a function is continuous iff for...
My question is:
Let f:\bigcup_{\alpha}A_{\alpha} \rightarrow Y be a function between the topological spaces Y and X=\bigcup_{\alpha}A_{\alpha}. Suppose that f|A_{\alpha} is a continuous function for every \alpha and that {A_{\alpha}} is locally finite collection. Suppose that A_{\alpha} is...
I read so much to reach the point about golden members :D I understood that those members have some control about the contents on the the forum , is that all the story ?
If I want to post a new thread or a new post , and if my post needs some mathematical statement , say in first order logic then I need to use Latex to make my posts readable , but it seems that the site doesn't support LaTeX ! then What to do ? any suggestions ?
There is a notice on my page here which tells me that I can get a golden membership by making a link to Physics Forums on my Website or Blog. But What is a golden membership?! What is the difference between it and my membership now?!
Here is the question in attachment , I make it as the site don't support LaTeX I think!
https://www.physicsforums.com/attachment.php?attachmentid=63439&stc=1&d=1383093152
take this example !
6 can't divide 3,4,5
but 6 can divide 3*4*5= 60
p can't divide any factor but maybe it can do this with some products of them like the example above ! why not ??
hi ,
this result is from text , Abstract Algebra by Dummit and foote .
page 120
the result says , if G is a finite group of order n , p is the smallest prime dividing the order of G , then , any subgroup H of G whose index is p is normal
and the text gave the proof of this result ...
prove , if x is a rational number , x ≠ 0 then , tan(x) is not rational
this theorem was proved by a mathematician called Lambert ,
I search for the proof , anyone knows it ?!
what is nice ? the music or hobbies ?!
hmm , I don't know this group " massar egbari " ! - can you tell me the name of one of them songs ? "
nowdays , many types of songs is avaliable in egypt , but I don't prefer these new kinds ,
I like ancient singers ! like Fayrouz if you know her