The general equation is
[tex]f(x)=A\sin (B(x+C))+D[/tex]
where A is the amplitude, the phase shift is C (if it is positive the shift is to the left), D is the vertical shift and the period is given as:
[tex]\frac{2\pi}{B}[/tex]
In this case we have the function:
[tex]g(x)=3\sin (2x)-1[/tex]
From this we notice that A=3, B=2, C=0 and D=-1; therefore:
Amplitude: 3
Phase shift is zero.
The vertical displacement is -1, this means that the function is translated vertically one unit down.
The period is:
[tex]\frac{2\pi}{2}=\pi[/tex]
The equation of the midline is:
[tex]y=-1[/tex]
The graph of the function is shown below:
here the red graph is the sine function, the blue graph is the function g and the green line is the midline.
