Problem:f(x) = -4 + 2 cos ^{1}/_{3} (x - 9°). On a sheet of paper, graph the function in degrees. Find:The function's amplitude, period, phase shift, vertical shift, and the four x-values that mark the location of its phase-shifted quartiles. Responses: amplitude = period = phase shift = vertical shift = quartile 1 = quartile 2 = quartile 3 = quartile 4 =