**Creating a 3D bar chart**

To create a bar chart:

• Define a matrix of values to display, Mathcad will use the rows and column numbers of the matrix as x- and y-axes, The matrix elements will be shown as columns extending from the xy plane to the appropriate height.

• Choose Graphy 3D Bar Chart from the Insert menu, Mathcad shows a box with a single placeholder, as shown below:

• Type the name of the matrix in the placeholder. Just as with an equation, Mathcad will not display anything until you click outside the plot region. What you see is a visual representation of the matrix. Mathcad draws a perspective view of the matrix as a two-dimensional grid lying flat in three-dimensional space. Each matrix element is represented as a column extending above or below this grid by an amount proportional to the value of the matrix element. In the default perspective, the first row of the matrix extends from the back left comer of the grid to the right, while the first column extends from the back left comer out toward the viewer.

The perspective on the bar chart depends on the location of the viewer with.respect to the surface. You can specify this view by changing the chart’s tilt or rotation, as described in “Changing your view of the 3D bar chart”.

**Displaying a function of two variables**

A typical 3D bar chart shows the values of a function of two variables. To see such a chart, you must first create a matrix that holds the values of the function, then create a bar chart of that matrix. Here are the typical steps in plotting a function of two variables:

• Define a function of two variables.

• Decide how many points you want to display in the x and y directions. Set up range variables i andj to index these points. For example, if you want to display 10 points in each direction, enter:

i:= 0 .. 9 j :=0 .. 9

• Define xi and Yj as evenly as evenly spaced points on the x- and y-axes.

• Fill the matrix M with the values off( xi’ Yj ).

• Choose Graph=>3D Bar Chart from the Format menu.

• Type M in the placeholder. Then click outside the plot region