Hi all, I wish to verify

with the shorthand notations being and for the following expression

where k is a constant and f is continous on the real line ( I actually dont understrand what that 'f' bit means)

Can anyone give me a clue as how to tackle this one? Do I integrate the integrand first and then find the derivatives ? If so, how does one tackle the integrand with the infinity signs etc?

Thanks, tips will be appreciated.

Looking forward to hearing from some one.

Bugatti79