1.73 The unity-gain voltage amplifiers in the circuit of Fig. P1.73 have infinite input resistances and zero output resistances and thus function as perfect buffers. Furthermore, assume that their gain is frequency independent. Convince yourself that the overall gain Vo/Vi will drop by 3 dB below the value at dc at the frequency for which the gain of each RC circuit is 1.0 dB down. What is that frequency in terms of CR?