How do you find the amplitude, period, and shift for y= 4cos(x/2+pi/2)?

1 Answer
Nov 21, 2015

The amplitude is 4, the period is 2pi, and there is an horizontal shift of -pi/2

Explanation:

There is a general equation for cosine
y = a*cos(b(x-c)) + d
where |a| is the amplitude
2pi/|b| is the period
c is the horizontal displacement
and d is the vertical displacement

|b| and |a| mean the value of a or b without the sign ( that is no positive or negative attached to the value)

So for your equation of y = 4*cos((x/2) + (pi/2))
a = 4
b = 1
c = -pi/2
d = 0
This makes your amplitude, 4
period, 2pi
horizontal displacement -pi/2
and no vertical displacement