Page 48 - A Guide to MATLAB for Beginners and Experienced Users

Graphics 29

2
To plot x + x + 1 on the interval from −2 to 2 we first make a list X of
x values, and then type plot(X, X.ˆ2+X+1). We need to use enough
x values to ensure that the resulting graph drawn by “connecting the dots”
looks smooth. We’ll use an increment of 0.1. Thus a recipe for graphing the
parabola is

>> X = -2:0.1:2;
>> plot(X, X.ˆ2+X+1)

The result appears in Figure 2-6. Note that we used a semicolon to suppress
printing of the 41-element vector X. Note also that the command

>> plot(X, f1(X))

would produce the same results (f1 is defined earlier in the section User-
Defined Functions).

7

6

5

4

3

2

1

0
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
Figure 2-6