Consider the circuit represented in a) where C1=7,08 nF, R1=139,1 KΩ and I1=1,5 mA.

Consider circuit b) and the values for Rth and Vth previously obtained.

It is known that the transient response of the voltage in the capacitor will be given by 

Vc_trans(t)= A. e^s.t

 Please give the value for parameter s. 

Hint: please have in mind that C1 is in nF and the resistors are in KΩ