Answer
The amplitude is 3
The period is $2\pi$
The vertical translation is 0
The phase shift is $-\frac{\pi}{2}$
Work Step by Step
$y = A~cos(Bx+C)+D$
$y = 3~cos(x+\frac{\pi}{2})$
$A = 3$
$B = 1$
$C = \frac{\pi}{2}$
$D = 0$
$\vert A \vert$ is the amplitude.
The amplitude is 3
$\frac{2\pi}{B}$ is the period.
The period is $2\pi$
$D$ is the vertical translation.
The vertical translation is 0
$\frac{-C}{B}$ is the phase shift.
The phase shift is $-\frac{\pi}{2}$
