The maximum power supply voltage for the TL084CDE4 is ±18V, or 36V total.
Yes, the TL084CDE4 has a bandwidth of 3MHz and a slew rate of 13V/μs, making it suitable for high-frequency applications.
Yes, the TL084CDE4 can be used in a single-supply configuration, but the input common-mode voltage range is limited to VCC-2V to VCC+2V.
To ensure stability, ensure that the feedback loop has a gain of less than 1 at the frequency where the phase shift is 180°, and use a capacitor in the feedback loop to compensate for phase shift.
The input impedance of the TL084CDE4 is typically 2MΩ, but can be affected by the input capacitance and the source impedance.