if D means the derivative respect to x , is always licit to use this operator ??(adsbygoogle = window.adsbygoogle || []).push({});

for example Ramanujan obtained his Master theorem from the integral equality

[tex] \int_{0}^{\infty} dx e^{-ax} x^{m-1} = \Gamma (m) a^{-m] [/tex]

by just replacing the 'a' number by the operator exp(D) and expanding exp(-exp(x) but is this valid ?? , can we always replace real numbers by operators ??

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# A question on the operator e^D

**Physics Forums | Science Articles, Homework Help, Discussion**