A Simple Derivation of Schroedinger Uncertainty Relation
  We show how the Schroedinger Uncertainty Relation for a pair of observables can be deduced using the Cauchy-Schwarz inequality plus successive applications of the commutation relation involving the two observables. Our derivation differs from the original one in the sense that we do not need the expansion of the product of these two observables in a sum of symmetrical and anti-symmetrical operators. 
Gustavo Rigolin