Exercise 39

If \(R\) is the total resistance of three resistors, connected in parallel, with resistances \(R_1\), \(R_2\), \(R_3\), then
\[ \frac{1}{R} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} \]
If the resistances are measured in ohms as \(R_1 = 25\,\Omega\), \(R_2 = 40\,\Omega\), and \(R_3 = 50\,\Omega\), with a possible error of 0.5% in each case, estimate the maximum error in the calculated value of \(R\).