\begin{tikzpicture}[line cap=round,line join=round,>=triangle 45,x=1cm,y=1cm]
\begin{axis}[
x=1cm,y=1cm,
axis lines=middle,
xmin=-5,
xmax=5,
ymin=-1.4,
ymax=5,
ytick={-1,...,4},
xtick={-3,...,3},
xlabel=$x$,
ylabel=$y$,
]


\addplot[domain=0.5:4, blue, line width=1,samples=50] {1/(x^2)};
\addplot[domain=-4:-0.5, blue, line width=1,samples=50] {1/(x^2)};

\node[] at (axis cs:2.5,2.5) {$\displaystyle y=\frac{1}{x^2}\; (x \neq 0)$};
\end{axis}



\end{tikzpicture}