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Given this circuit:

enter image description here

All the ops are ideal (infinite gain, infinite bandwidth, infinite input resistance and zero output resistance.

I have to calculate the 3 dB frequency of this amplifier which is defined as follows:

$$\frac{V_{\text{out}}}{V_1 - V_2}=A_d$$

Calculating the entire transfer function of this amplifier to its 3 dB frequency is a quite a tedious task and I assume there must be a shortcut method which I'm unfamiliar with, that might make evaluate the 3 dB frequency of this amplifier much more easily. Can the constants time method be applied here? How can I use the symmetry in this circuit to evaluate the 3 dB frequency?

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    \$\begingroup\$ You have two, 1st order lowpass filters, summed up with a 3rd, 1st order lowpass. \$\endgroup\$
    – a concerned citizen
    Commented Mar 4, 2022 at 15:03
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    \$\begingroup\$ As near as damn it 3978 Hz - no point being ultra accurate cause the resistor tolerances will have a bigger effect than me ignoring the (largely irrelevant) final stage 3 dB point \$\endgroup\$
    – Andy aka
    Commented Mar 4, 2022 at 15:09
  • \$\begingroup\$ This looks like a homework question...otherwise you could just simulate the circuit. We will need you to show us that you have made a substantial effort to solve this yourself. Show us all of your work. \$\endgroup\$
    – Elliot Alderson
    Commented Mar 4, 2022 at 15:32
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    \$\begingroup\$ Is the missing capacitor across R11 on purpose? \$\endgroup\$
    – qrk
    Commented Mar 4, 2022 at 16:46

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