What would be the most performing way to check whether a number of degrees (e.g. $10^\circ$) is within a range of degrees $\pm 30^\circ$ outgoing from $355^\circ$?
For a better understanding of my (novice) question, here's an image I just painted. a is the heading I want to check, b is the given heading with the tolerance of $\pm30^\circ$.
EDIT: The range can possibly be up to $180$ degrees (dynamically).
