1. The problem statement, all variables and given/known data Show the following identity (in the sense of distribution): [tex]g(\bold x)\delta (\bold x)=g(\bold 0) \delta (\bold x)[/tex] for a function g. 2. Relevant equations No idea. 3. The attempt at a solution I don't have a concrete idea about what a distribution is (It's an assignment in my electromagnetism course and we've not been introduced the required math so I guess I should search in books, but I don't know which ones and the article http://en.wikipedia.org/wiki/Distribution_(mathematics) in wikipedia doesn't seem easy to understand for me). From the identity, I get the idea that [tex]\delta (\bold x)[/tex] is 0 everywhere except in [tex]\bold x=0[/tex] but I'm not sure and even if it were so, I don't really understand why the equality holds. Any help is greatly appreciated.