The marginal revenue, when x = 15 is
(A) 116
(B) 96
(C) 90
(D) 126
6 3  Increasing and Decreasing Functions
In this section, we will use differentiation to find out whether a function is increasing or
decreasing or none Consider the function f given by f (x) = x2, x ∈ R The graph of this function is a
parabola  as given in Fig 6