What is the Differential Equation for the Current in an Auto Induction Circuit?

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The discussion revolves around finding the differential equation for current in an auto induction circuit after a switch is opened. The user has proposed the equation (R+r)*i + L(di/dt) = 0 but is uncertain whether to include the total resistance (R+r) or just the resistance r in the equation. There is a request for clarification on the correct formulation of the differential equation. The user expresses frustration over the lack of responses to their query. The thread highlights the challenges faced in understanding circuit dynamics and the need for expert guidance.
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Homework Statement


i tried to put all data in the image .

http://img136.imageshack.us/img136/7443/photokg6.th.jpg

in the initial situation K was closed.in T = 0 ,K was opened.

give the differenciel equation of the courant.

The Attempt at a Solution



(R+r)*i + L (di)/(dt) = 0 .

my problem is that i don't know if we have to put (R+r)*i or only r*i in the differentiel equation of the courant .

thanks in advance for any help.
 
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by the way,if there is something not clear in the data of the problem ,i will be happy to explain it.
 
does nobody know the solution?
 
no answer !:(
 

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