\documentclass{standalone}

\pagestyle{empty}
\usepackage{tikz}
\begin{document}

\begin{tikzpicture}

\draw [ultra thin,cyan,->] (-1,0)--(6,0);
\draw  [ultra thin,cyan,->] (0,-1.2)--(0,1.2);
\draw  [ultra thin,cyan,->] (5,-1.2)--(5,1.2);

\draw (-1,-1)--(0,-1);
\draw (0,1)--(5,1);
\draw (5,1)--(6,1);

\draw[red, smooth, domain=-1:6] plot function {4*  (sin(pi *x/ 5) )/pi};
\draw[orange, smooth, domain=-1:6] plot function {4*  (sin(pi *x/ 5) + sin(3*pi *x/ 5)/3 )/pi};
\draw[green, smooth, domain=-1:6] plot function {4*  (sin(pi *x/ 5) + sin(3*pi *x/ 5)/3 + sin(5*pi *x/ 5)/5 )/pi};
\draw[blue, smooth, domain=-1:6] plot function {4*  (sin(pi *x/ 5) + sin(3*pi *x/ 5)/3 + sin(5*pi *x/ 5)/5 + sin(7*pi *x/ 5)/7 )/pi};
\draw[violet, smooth, domain=-1:6] plot function {4*  (sin(pi *x/ 5) + sin(3*pi *x/ 5)/3 + sin(5*pi *x/ 5)/5 + sin(7*pi *x/ 5)/7 + sin(9*pi *x/ 5)/9 )/pi};
\end{tikzpicture}
\end{document}