Abstract
By a purely infinitesimal method we derive the eigenvalues of the Biedenharn's invariant operators from I2 to I6 for the SU(n) group. We show that the general formula, quoted from the Racah's work by Baird and Biedenharn, to obtain the eigenvalues of the invariant operators, is valid only for the two first I2 and I3 operators and not for the higher order invariants. We give the correct values for the first invariants till I6.