Where is the midline of this function?

the midline is the line:

y = 0.

Step-by-step explanation:

The midline of a function is a horizontal line that divides evenly the graph of the function in two parts.

Particularly, for trigonometric functions, we usually have:

f(x) = A*sin(k*x + p) + M

Where:

A is the amplitude.

x is the variable

k is a constant related to the frequency of the function.

p is a phase shift

M is the midline of the function, which means that the line that divides evenly the graph is y = M.

For our case, we have:

y = f(x) = 3*sin(2*x - π)

Then:

A = 3

k = 2

p = -π

And we do not have a constant term in that equation, this means that:

M = 0

This means that the line that divides evenly the graph is the line y = 0.