Let's consider this circuit:
and suppose that the capacitor C1, charged at the input voltage Vin, at time t=0 is connected by the switch to the virtual ground. Assume also that C and C0 are initially discharged.
First question: How does the book I'm reading show that:
Second question: If C1 has an initial voltage vin, how can the switch modify the voltage of C1 to the virtual ground? I know that the voltage across a capacitor cannot change instantly.