Suppose that f(x) = 3x\\ 4x2 + 1 (A) Find all critical values of f. If there are no critical values, enter None . If there are more than one, enter them separated by commas. Critical value(s) = (B) Use interval notation to indicate where f(x) is increasing, or type {} if it is increasing nowhere. Increasing: (C) Use interval notation to indicate where f(x) is decreasing, or type {} if it is decreasing nowhere. Decreasing: (D) Find the x-coordinates of all local maxima of f. If there are no local maxima, enter None . If there are more than one, enter them separated by commas. Local maxima at