Coordinate space and momentum space

1. Sep 11, 2008

Felicity

1. The problem statement, all variables and given/known data

given A(k)=N/(k2+a2) calculate psi(x) and show that

(delta k * delta x) > 1

independent of the choice of a

3. The attempt at a solution

I calculated psi(x) to be (N*pi/a)*e-|ax|

Would it be ok to compute <x> and <x2> in coordinate space and <k> and <k2> in momentum space (which gives me simple multiplication for all my operators) and then find (delta x * delta k) using

delta x = sqrt(<(x-<x>)>) and delta k = sqrt(<(k-<k>)>) ?

do i have to transform anything before I do this? How would I do that?

Thank you