TeX source:
\begin{aligned} &\begin{array}{l|l} {\mathrm{x}} & \mathrm{f}(\mathrm{x}) \\ \hline 0.9 & 2.82 \\ 0.9998 & 2.9996 \\ 0.999994 & 2.999988 \\ 0.9999999 & 2.9999998 \end{array} \\ &\begin{array}{ll}\qquad \downarrow & \qquad \qquad \downarrow \\ \qquad 1 & \qquad \qquad 3 \end{array} \end{aligned}