1. The problem statement, all variables and given/known data While using a current balance to experimentally determine mu0 (4PI*10-7), two mu0 values were found (current was reversed to find one of these values) and averaged together in order to partially compensate for the effect of the earths field. Why does the flipping compensate for this and how can I prove it using taylor series expansion? 2. Relevant equations f(x+e) = f(x) + f'(x)e + 0(eR) 3. The attempt at a solution I am not sure how to begin a proof of this!