Graph the function if the given changes are made in the indicated examples of this section.

In Example 2, if the sign of the coefficient of cos x is changed, plot the graph of the resulting function. 

Data from Example 2

Plot the graph of y = −3 cos x.

In this case, a = −3, and this means that the amplitude is −3 = 3. Therefore, the maximum value of y is 3, and the minimum value of y is −3. The table of values follows, and the curve is shown in Fig. 10.6.

X y X 0 6 -3 -2.6 -1.5 0 1.5 2.6 3 11 6 3 y 2.6 1.5 2 3 5 27 1.5 0 -1.5 -2.6 -3