Answer:
[tex]- \frac{\pi}{3}[/tex]
Step-by-step explanation:
Given
[tex]y = -3\cos(3x - \pi) + 5[/tex]
Required
The phase
We have:
[tex]y = -3\cos(3x - \pi) + 5[/tex]
Rewrite as:
[tex]y = -3\cos(3(x - \frac{\pi}{3})) + 5[/tex]
A cosine function is represented as:
[tex]y = A\cos(B(x + C)) + D[/tex]
Where:
[tex]C \to[/tex] Phase
By comparison:
[tex]C = - \frac{\pi}{3}[/tex]
Hence, the phase is: [tex]- \frac{\pi}{3}[/tex]