- #1
quietrain
- 655
- 2
i don't really understand the dirac delta function in 3D.
is it right that integral of f(r)d3(r-a)dt = f(a)
where a = constant ,r is like variable x in 1D dirac delta function?
so why when i have f(r')d3(r-r') , it picks out f(r)?
where r is now a constant and r' is a variable
shouldn't it be f(r')d3(r'-r), then it picks out f(r) ?
it is as though saying that (r-r') = (r'-r) when we use dirac delta function?
thanks!
is it right that integral of f(r)d3(r-a)dt = f(a)
where a = constant ,r is like variable x in 1D dirac delta function?
so why when i have f(r')d3(r-r') , it picks out f(r)?
where r is now a constant and r' is a variable
shouldn't it be f(r')d3(r'-r), then it picks out f(r) ?
it is as though saying that (r-r') = (r'-r) when we use dirac delta function?
thanks!