Question: Integral devision by zero

Hello,

For a control systems project I'am working on I need to minimize the actuator effort required to control an input voltage to certain output voltage. As a first experiment I chose a sinusoidal input ug and a sinusoidal output ul. The function to minimize is the funtion Uint. We know that when both the input voltage and output voltage share the frequency, phase and amplitude, that the control effort is zero. Running the animation (see Maple input below) shows that if the input and output voltage frequencies approach eachother the function Uint goes to zero. However, if the frequencies exactly match and I evaluate the function Uint I get a devision by zero notification (this could already be seen from the function of Uint). How can I solve this?

Download 20131109_Division_by.mw

Thanks