Merge pull request #41 from pritomshad/pritomshad-patch-typo-fix-1

typo fixed principal_argument.html

Author: jcponce

content/principal_argument.html

@@ -184,7 +184,7 @@ <h2>
             </h2>
 
             <p>
-                If  $z_1= r_1e^{\theta_1}$ and $z_2= r_2e^{\theta_2},$ then
+                If  $z_1= r_1e^{i\theta_1}$ and $z_2= r_2e^{i\theta_2},$ then
                 \begin{eqnarray}\label{product}
                 z_1z_2 = \left(r_1r_2\right)e^{i\left(\theta_1 + \theta_2\right)}
                 \end{eqnarray}