I fixed the bracket issue, I apologize about that.
I am concerned with the (r/l) term inside of the equation. I understand that asin(sin(x))=x .. but I'm certain that asin(sin(x)(r/l)) --DNE-- (r/l)x
I am using the Law of Cosines to extract and angle I need from a shaft that is turning on an air engine by piston oscillation and I am having a brain fart on if there are any identities I am missing that can help me pull '\alpha' from the right side of my equation...