The voltage, , (in volts) across a circuit is given by Ohm's law: , where is the current (in amps) flowing through the circuit and is the resistance (in ohms). If we place two circuits, with resistance and , in parallel, then their combined resistance, , is given by . Suppose the current is amps and increasing at amp/sec and is ohms and increasing at ohm/sec, while is ohms and decreasing at ohm/sec. Calculate the rate at which the voltage is changing. Round your answer to three decimal places.