Practical 2: Variables, Script M-files and Graphing

> Create and run a script M-file called plotMe.m for the following command. Remember to add your comment headers at the top.

plot([1 3], [2 5])

Note: The graph will appear in a separate Figure Window named Figure 1 that is often hidden behind the main MATLAB window. Maximise it on your taskbar if it does not pop up.

> What does the graph look like? Verify which points of 1, 2, 3, 5 are $x$-coordinates or $y$-coordinates.

> Modify your plotMe script M-file to plot the functions $y = 3x + 2$ and $z=4x$ over the region of $1 \le x \le 3$ by following these steps.

1. Define the endpoints of $x$ as the two variables $x_{1}$ & $x_{2}$.
2. Define the endpoints of $y$, as the two variables $y_{1}$ & $y_{2}$, in terms of $x_{1}$ & $x_{2)$.
3. Change the plot command to:
   plot([x1 x2], [y1 y2])
4. Run your file to check that your updated graph is correct.
5. Define the endpoints of $z$, as the two variables $z_{1}$ & $z_{2}$, in terms of $x_{1}$ & $x_{2}$.
6. Change the plot command so that both lines are plotted on one graph as follows:
   plot([x1 x2], [y1 y2], [x1 x2], [z1 z2])
7. Check that your updated graph is correct.