MATLAB Examples

# Section 8 - Visualizing Data

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## Line Plots in Two Dimensions

```simple_x_points = [1 2 3 4 5] ```
```simple_x_points = 1 2 3 4 5 ```
```simple_y_points = [25 0 20 5 15] ```
```simple_y_points = 25 0 20 5 15 ```
```plot(simple_x_points, simple_y_points); ```
```plot(simple_y_points, simple_x_points); ```
```plot(simple_x_points, simple_y_points); xlabel('this is text describing the x-axis'); ylabel('this is text describing the y-axis'); title('this is text giving a title for the graph'); grid on; ```
```x_points = [-5 : .1 : 5]; y_points = x_points .^ 2; plot(x_points,y_points); xlabel('x-axis'); ylabel('y-axis'); title('A Parabola'); grid on ```

## Multiple Plots and Subplots

```x_points = [-10 : .05 : 10]; plot(x_points, exp(x_points)); ```
```grid on hold on plot(x_points, exp(.95 .* x_points)); plot(x_points, exp(.85 .* x_points)); plot(x_points, exp(.75 .* x_points)); xlabel('x-axis'); ylabel('y-axis'); title('Comparing Exponential Functions'); ```
```x_points = [-10 : .05 : 10]; line = 5 .* x_points; parabola = x_points .^ 2; exponential = exp(x_points); absolute_value = abs(x_points); subplot(2,2,1);plot(x_points,line); title('Here is the line'); subplot(2,2,2);plot(x_points,parabola); title('Here is the parabola'); subplot(2,2,3);plot(x_points,exponential); title('Here is the exponential'); subplot(2,2,4);plot(x_points,absolute_value); title('Here is the absolute value'); ```

## Line Plots in Three Dimensions

```clf; % clear the figure X = [10 20 30 40]; Y = [10 20 30 40]; Z = [0 210 70 500]; plot3(X,Y,Z); grid on; xlabel('x-axis'); ylabel('y-axis'); zlabel('z-axis'); title('Pretty simple'); ```
```Z = [0 : pi/50 : 10*pi]; X = exp(-.2.*Z).*cos(Z); Y = exp(-.2.*Z).*sin(Z); plot3(X,Y,Z); grid on; xlabel('x-axis'); ylabel('y-axis'); zlabel('z-axis');... title('A little more interesting!'); ```

## Three-Dimensional Surface Mesh Plots

```x_points = [-10 : 1 : 10]; y_points = [-10 : 4 : 10]; [X, Y] = meshgrid(x_points,y_points); Z = X.^2 + Y.^2; mesh(X,Y,Z); xlabel('x-axis'); ... ylabel('y-axis');zlabel('z-axis'); ```