Let y= -11cos[3(x-pi/3)]

Question

1. What is the amplitude?
2. What is the period?
3. What is the phase shift?

Answer 1

If y = Acos(Bx + C) or y = Asin(Bx + C), where B > 0 then

Amplitude = l A l

Period = 2π / B

Phase shift = -C / B

So, for y = -11cos[3(x - π/3)] = -11cos(3x - π),

Amplitude = 11

Period = 2π / 3

Phase shift = π / 3