\begin{array}{|c|c|c|}\hline x&-2&-1&0&1&2\\\hline y=x^2&4&1&0&1&4\\\hline \end{array}
\begin{array}{|c|c|c|}\hline x&-2&-1&0&1&2\\\hline y=\dfrac{1}{4}x^2&1&\dfrac{1}{4}&0&\dfrac{1}{4}&1\\\hline \end{array}
\begin{array}{|c|c|c|}\hline x&-2&-1&0&1&2\\\hline y=\dfrac{1}{2}x^2&2&\dfrac{1}{2}&0&\dfrac{1}{2}&2\\\hline \end{array}
\begin{array}{|c|c|c|}\hline x&-2&-1&0&1&2\\\hline y=-\dfrac{1}{4}x^2&-1&-\dfrac{1}{4}&-0&-\dfrac{1}{4}&-1\\\hline \end{array}
