1. The problem statement, all variables and given/known data We have a capacitor in parallel with an inductor. These are both in series with a resistor and capacitor. Calculate the J notation Impedance of the network. I only want the initial basic solution. The problem I have is that sometimes the J notation of C is -ve and sometimes +ve ? 2. Relevant equations 3. The attempt at a solution Product/sum of the parallel cct: jwL x 1/jwC/jwL*1/jwC This is the Inductor and capacitor impedance equation. The above will be added to: R -j(1/wC) My question is therefore, why in the above example at product over sum would it be ok to say jwL x 1/jwC/jwL*1/jwC i.e. * a +ve 1/jwC When below it I can add it to R and -j(1/wC) I hope this makes sence, thanks for any help in advance.