CPM Homework Help : PC Problem 9-101

The graph below is the result of a transformation of $y = \sin x$ . Find a possible equation for the function.

Hint:

The vertical shift is down $4$ . There is no horizontal shift.

More help 1:

So a whole cycle (period) is $4π$ . Calculate the frequency $b$ : $bp = 2π$ , so $4πb = 2πb =$ ?

More help 2:

Substitute pertinent information into: $y = A\sin\left(b\left(x\right)\right) ± C$

Periodic curve, x axis scaled from negative 2 pi to 2 pi, with 2 visible turning points at (negative pi, comma negative 5), & (pi, comma negative 3), with y intercept at (0, comma negative 4).