So I understand how these kind of question but my question i

So I understand how these kind of question, but my question is in regard to the 5 ohm resistor, why is the 5k resistor just discarded when t<0 and we make the inductor a short line.

Example In the circuit shown, find i(t) for t>0. Assume the switch was closed for a long time. 12 8 24 i(t) 5 12 (324 2MA

Solution

When inductor acts as short circuit it is replaced with short that is 0 ohm resistance.

When 0 ohm resistance parallel with 5 ohm the equivalent resistance is (5*0)/(5+0) = 0 ohm

Therefore it is neglected.