Explanation:
We know that the function period is 3 so the b value is
So our b is 2 pi/3.
The midline is -3 and the amplitude is 2.Since this function isn't symmetric about y axis, and looks symmetric about orgin, we trig function will be Sine so we have
The function passes through 0,-3 and our function on the graph passes through 1,-3 so we shift one unit to left.