Hey guys, need help with a problem here. Sorry for the quality of the image. I understand that above the op-amp, is the active low pass filter. So if I were to figure that out with respect to V2 and Vout, it would just be Vout/Vs = -(Zf/Zs) where Zf = (Rf/(1+jwCfRf)) Zs = Rs But I don't understand how the bottom setup comes into the equation. I realize it must also be a filter and should be solved wrt V1. And I am asked to find the transfer function Vout/V1-V2. All help would be greatly appreciated.