AC Light Bulb Fade Circuit - Resistors Getting Hot!
It is non-trivial to calculate the power dissipated in the resistors.  The input is 120 AC with a peak voltage of ~170V.

With the voltage at the capacitor being 90V the drop across the resistors is a truncated sine wave with a peak of about 80V.

The easiest way to calculate the power dissipation is to use a free simulator such as LTSpice.

I changed the order of the diode and resistors to make probing the voltages easier but it won't make any difference to the results.

I used a voltage source instead of the capacitor and resistor to speed-up the simulation - it was taking ages to reach 90v.



In the plot shown the Blue trace is the incoming AC, Green is the voltage at the diode output and the red trace is the instantaneous power in each resistors, note that it peaks at about 15W.

LTSpice then did the average of the power plot to give 2.9W in each resistor.