My question is, does C(E) and r(E)(not showed) at Q1 have effect on the lower or upper -3dB frequency? I think there is, depending on the value of the C(E). Am I correct?
But the solution give for this question is:
Lower -3dB:
decide by : R(L1)//H(oe)+R3//R4 and C(c)
Upper -3dB:
decide by: R(L1)//H(oe)//R3//R4 and C(s)