Hi, I think I have found a typo in section titled Current Division on page 8 of Chapter 2.2: Parallel Circuit Elements and Current Division.
This is in Real Analog - Circuits 1.
Equation 2.17 states i1 = [1/R1] x [i/(1/R1 +1/R2)] which you state simplifies to i1=[R2/(R1+R2)] eqn 2.18
Surely the correct equation is i1=[R2/(R1+R2) x i]. The same with eqn. 2.19.