A circuit contains an ideal battery of emf \(\varepsilon = 18\text{ V}\), two resistors, an open switch, and an uncharged capacitor of capacitance \(C = 10\text{ }\mu\text{F}\). At time \(t = 0\), the switch is closed, and the potential difference \(V_C\) across the capacitor is measured as a function of time \(t\), as shown in the graph. The dashed horizontal line represents the steady-state asymptote, and the dashed diagonal line is tangent to the curve at \(t = 0\). Based on the graph, what is the equivalent resistance of the circuit connected across the capacitor?