To determine the total resistance [tex]\( R \)[/tex] in a parallel circuit with individual resistances [tex]\( r_1 \)[/tex], [tex]\( r_2 \)[/tex], and [tex]\( r_3 \)[/tex], we use the formula:
[tex]\[
\frac{1}{R} = \frac{1}{r_1} + \frac{1}{r_2} + \frac{1}{r_3}
\][/tex]
This is the correct formula because, in a parallel circuit, the reciprocal of the total resistance is the sum of the reciprocals of the individual resistances.
