\nabla{F} = \left[\begin{array}{cccc}
1 & 0 & \cdots & 0 \\
0 & 1 & \cdots & 0 \\
0 & 0 & \cdots & 0 \\
\cdots & \cdots & \cdots & \cdots \\
\frac{\partial{f}}{\partial{x_1}} & \frac{\partial{f}}{\partial{x_2}} & \cdots & \frac{\partial{f}}{\partial{x_{n-1}}}
\end{array}\right]