We have a circuit consisting of a charged capacitor and a resistor. First of all, we use Kirchhoff's loop rule to express this circuit in mathematical form. Now one teacher tells me Kirchhoff's loop rule yields iR+q/c=0. Another teacher tells me that the rule yields iR-q/c=0. Is there any way to reconcile these two interpretations? They seem to contradict. Carrying out the derivation, if we use the first equation, we simply replace i=dq/dt. If we use the second equation we have to replace i=-dq/dt. Which of these routes is justified? I can't imagine that they are both valid.