[…] Because the graph of this function is in four-dimensional space, you can't directly plot the graph of the function. However, you can visualize the locations of the zero(s) by plotting the magnitude (norm) of the function. In the following graph, I use the contour plot in SAS/IML Studio to graph the quantity || f || = sqrt(f12 + f22) on a uniform grid of (x1, x2) values. …