The current going into the inverter will not be constant. This will be a sinewave and you are implying that you have a flat 1A dc current flowing into the oscillator, which I doubt will be the case. If this is the case, then the extra power will be used up as heat in the oscillator. Also, I notice that you have 0-10V going into the oscillator, yet have a +/-10V signal coming out. This will further complicate the case. This sounds like Homework Help, but the answer is not that straight forward