9.) [16 pts.] In the circuit below, assume that SWI and SW2 is closed (connected) [Note: the diagram below shows the switches in the open position. But assume they are closed for this problem]. Use the generalized concept of a voltage divider (review your notes/lecture slides) to find expressions for the voltage V1 and V4 in the circuit below. Your expression should be in terms of Vs and RI-R4. R1 Vs + V1 - R2 www V2- SW2 R4 SW1 R3 V4 V3 - Note: V3 is the voltage across the series of SW1 and R3 Note: V4 is the voltage across the series of SW2 and R4 10.) [6 pts.] Look at the circuit from problem 9 and reuse the equation you found. If SW2 is now open (not connected) but SW1 is still closed (connected) derive an expression for V4 (voltage across SW2 and R4)? Your expression should be in terms of Vs and (possibly) some of R1-R4. Hint: Remember a switch can be modeled as either a VERY LARGE (infinite) resistance or VERY SMALL (zero) resistance. With SW2 open, what resistance value can be used to model the effect of SW2 and R4?