Đáp án:
$\begin{array}{l}
{R_1}//{R_2}//{R_3}...{R_n}\\
\frac{1}{{{R_{td}}}} = \frac{1}{{{R_1}}} + \frac{1}{{{R_2}}} + \frac{1}{{{R_3}}} + ...\frac{1}{{{R_n}}}\\
\frac{1}{{{R_{td}}}} > \frac{1}{{{R_1}}};\frac{1}{{{R_{td}}}} > \frac{1}{{{R_2}}};\frac{1}{{{R_{td}}}} > \frac{1}{{{R_3}}};...;\frac{1}{{{R_{td}}}} > \frac{1}{{{R_n}}}\\
\Rightarrow {R_{td}} < {R_1};{R_{td}} < {R_2};{R_{td}} < {R_3};...{R_{td}} < {R_n}
\end{array}$
