How do I find a midline on a graph, from an equation? it is 2y=acos (bx+c)+d
y = (a/2)cos[b(x+(c/b)] + d/2
midline y= d/2
amplitude = a/2
period = 2pi/b
phase shift = c/b to the left
I have plotted a graph to show you what is happening. The two graphs start the same. Move the sliders to show you what happens as the letters change in value.
I hope that you understand what I am trying to show you.
If I or someone else, can explain further, let us know.
Another source of information