Begun logistic regression, added missing figures

writeup.tex

@@ -259,5 +259,14 @@ the calculation of the hypothesis function. The results of $\alpha=1.2,
     \label{PolynomialAlphaLambdaFunc}
 \end{figure}
 
+\section{Logistic Regression}
+\subsection{In the \code{logistic\_regression} folder, fill out the
+\code{sigmoid(z)} function in \code{sigmoid.m}}
+\begin{lstlisting}
+function output=sigmoid(z)
+    % Implement sigmoid function as shown in the sigmoid function formula.
+    output = 1.0 ./ (1.0 + exp(1) .^ -z);
+\end{lstlisting}\leavevmode \\
+
 % \printbibliography
 \end{document}