Added 1.18

Chapter1.tex

@@ -235,8 +235,14 @@
     \end{circuit}
 
     Now we have a simple RC circuit which we can apply Equation 1.21 to. The voltage across the capacitor is given by 
-    \[V(t) = V_\text{final}(1 - e^{-t/RC}) = V_\Th (1 - e^{-t/R_\Th C} = \frac{1}{2}V_\in (1 - e^{-t\times 10^{-3}})\]
+    \[V(t) = V_\text{final}(1 - e^{-t/RC}) = V_\Th (1 - e^{-t/R_\Th C} = \mans{\frac{1}{2}V_\in (1 - e^{-t\times 10^{-3}})}\]
 
     \todo{Add graph}
-
+
+    \ex{1.18}
+    From the capacitor equation in the previous paragraph, we have 
+    \[V(t) = (I/C)t = (1 \m\A/1\u\F)t = 10\V\]
+    This gives us
+    \[\mans{t = 0.01\text{s}}\]
+
 \end{document}