Homework Statement
The following circuit is given.
I intend to calculate the current in every resistor (every quantity except i1, i2, i3, is known).
My textbook states that ℰ3-ℰ1 = (R1+R2+R3+R4+2r)*i, but I think it should be -ℰ3+ℰ1 on the left-hand side, since the current enters the negative...