To find the vertical shift of a trigonometric function you will need to take a close look at the function that you are viewing. Let's start with the most basic function and move forward from there.
As you can see no shifts are happening to this function but if we add to the function a value of +3 the function is going to get shifted 3 values up in the
The same concept applies if you use the same function and you shift it down -3 values in the
The values that you add or remove from the base function are not co-dependent in any way. If you want to shift the function in the vertical direction you just have to add or remove from the base function.