A sine function has the following key features:

Frequency  = 1 / period

  1/(4pi) = 1/period       Period = 4 pi      2pi / 4pi = 1/2

Amplitude = 2

Midline = 2    ( this means it is shifted UP 2 from its usual midline of y=0

Y intercept  0,2

2 sin (1/2x) +2  

We have the form

y = Asin (Bx + C) + D

A = the amplitude =  2

The period =  4pi

Thus....in 2pi....there is (1/2) of a period.....so "B" =  (1/2)

There is no phase shift....so......C = 0

Since the midline is 2, then D =  2

So  the equation is 

y =   2sin ( 1/2 * x) + 2    =  2sin (x/2) + 2

Here:  https://www.desmos.com/calculator/o4e9ngaqie

Here is graph: