Step-by-step explanation:
We know that the function period is 3 so the b value is
[tex] \frac{2\pi}{b} = 3[/tex]
[tex]b = \frac{2\pi}{3} [/tex]
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
[tex]2 \sin ( \frac{2\pi}{3}x ) - 3[/tex]
The function passes through 0,-3 and our function on the graph passes through 1,-3 so we shift one unit to left.
[tex]2 \sin(\frac{2\pi}{3}(x + 1) ) - 3[/tex]