cleanup: fix some terminology

Lab1.tex

@@ -143,8 +143,8 @@ expressed as:
   of two components $v = v_a + v_b$, where the two components are of
   different frequencies, it can be shown from Equation ~\ref{eq:rms}
   that the RMS voltage $V_{RMS}$ of the combined signal is equal to
-  the sum of the squares of the RMS voltages of its additive
-  components, i.e.
+  the root of the sum of the squares of the RMS voltages of its
+  additive components, i.e.
 
   \begin{equation*}
     \label{eq:rms_sq_comp}