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 (x) and then evaluating Enter the domain in interval notation. the derivative at x 86 f(x) = = 2-86x. Domain of f'(x): f' (-86) ab sin (a) E