How do I modify the final current equation so that...?

Hi

Please have a look on the attachment. My main question is at the end. How do I modify the final current equation so that it adjusts for the discharging up to only 27V? Please help me. Thank you.

The answer given is: 4.5 + 5/6 e^(-t/0.15) mA

Regards
PG

Here is the solution:

Page 1: https://img535.imageshack.us/img535/8083/page1nu.jpg
Page 2: https://img263.imageshack.us/img263/1313/page2zp.jpg

Hi,

The answer for the voltage comes out to 5*e^(-t/(1500*100e-6))+27 because the 27 subtracts from 32 and the 27 is the final voltage.

However, it's probably better to do this circuit using the capacitors initial voltage as a third voltage source in the circuit, which after t=0 there will be two voltage sources. With the added new voltage source in series with the capacitor the voltage would be 32v and then the initial cap voltage would be 0. You then handle this simply as a two source circuit (after t=0) and dont have to worry about using any special techniques. The analysis is more straightforward like this.