The Seventh Gate As you approach the seventh gate, you notice that it is only a short distance to the area where your computer indicated the communication device was stored. You look past the gate hopefully, as your computer translates: The passcode for this gate is found by determining the domain of the derivative of f (@) and then evaluating the derivative at c = 28 82 Enter the domain in interval notation. f (x) = V8 - 821. Domain of f (x): 28 82