 In the time formula_92 that it takes for the resonant terms to complete one full oscillation, the anti-resonant terms will complete many full cycles.Since over each full cycle formula_93 of anti-resonant oscillation, the effect of the anti-resonant terms is 0, the net effect of the quickly oscillating anti-resonant terms tends to average to 0 for the timescales over which we wish to analyze resonant behavior.We may thus neglect the anti-resonant terms altogether, since their value is negligible compared to that of the nearly resonant terms.