RL Circuit Discharge and RCL Circuit

[xswtxoj]

In the RL Circuit Discharge and RCL Circuit, if you had only measured the resistance of your resistor and not taken into account the resistances in the inductor and function generator, how would this affect the calculated inducted from the half life measurement?

 

[rl.bhat]

how would this affect the calculated inducted from the half life measurement?
Can you write down the formula to calculate inductance from the half life measurement?