Answer:
1) Amplitude = 4
2) Frequency =

3) Initial phase =

Step-by-step explanation:
The general equation of wave is

where
A is the amplitude of the wave
is the angular frequency of the wave
is the initial phase of the wave
The given wave function is

Comparing with the standard function we get
1) Amplitude = 4
2) Frequency =

3) Initial phase =
