How dirac delta function can be used through integral

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Dirac delta function is a singular distribution. So, unlike regular distributions, it isn't defined by integration against test functions because test function multiplied by Dirac delta function is undefined at $0$.

As a distribution, it is expressed as $f\{g\}=g(0)$.

\begin{align*} \int_{-\infty}^{\infty} f(x)\frac{\mathrm{d}\delta(x)}{\mathrm{d}x} \, \mathrm{d}x &= f(x)\delta(x)\biggr|_{-\infty}^{\infty} - \int_{-\infty}^{\infty} \frac{\mathrm{d}f(x)}{\mathrm{d}x}\delta(x) \, \mathrm{d}x \\ &= - \int_{-\infty}^{\infty} \frac{\mathrm{d}f(x)}{\mathrm{d}x}\delta(x) \, \mathrm{d}x \end{align*}

And I read about its property about derivative in the above formula. Here, I have doubts, how it can be derived with partial derivative regardless of its non integrable?