Mathematica Stack Exchange is a question and answer site for users of Mathematica. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Why mathematica doesnt produce any answer to the following integral?

Integrate[0.040608386793220284*DiracDelta[w]*DiracDelta[-w + x], {w, -2, 2}]

and how can I get a solution?

Thank you very much.

share|improve this question
Have a look at 12000 – b.gatessucks Oct 18 '13 at 14:55
@b.gatessucks than you very much – Seyhmus Güngören Oct 18 '13 at 21:22
Thanks @b.gatessucks. – Seyhmus Güngören Oct 19 '13 at 16:23

Because you are using it incorrectly. The integral of a delta function is 1 when taken over all values:

Integrate[0.0406*DiracDelta[w]*DiracDelta[-w + x], {w, -Infinity, Infinity}]

gives the expected

0.0406 DiracDelta[x]
share|improve this answer
but I am interested in the integral only in this range, not from minus infty to plus infty. – Seyhmus Güngören Oct 18 '13 at 14:59
then specify x.. it can't know the value unless it knows x. Observe that Integrate[0.0406*DiracDelta[w]*DiracDelta[-w + 100], {w, -2, 2}] gives 0. – bill s Oct 18 '13 at 15:18
Integrate[f[x - w] DiracDelta[w], {w, -2, 2}, Assumptions -> x [Element] Reals && x [Element] Reals] /. f -> DiracDelta – Seyhmus Güngören Oct 18 '13 at 16:16

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.