does anyone know how i can use matlab/simulink to derive the time solution for a simulated series LCR circuit? (i have the simulation of the step responce from the transfer function)

 

not sure what you're asking

are you asking how Matlab can spit out the expression for the output in the time domain, given an input?

 

The attached Scilab based simulation of a series LCR circuit is probably what the OP has in mind. It uses an incremental (time-stepped) method to find the solution of the differential equations which describe the circuit behavior.

 

see attached image

 

i have completed 2, but is not sure what 3 is asking me to do