Consider a function f(x), with domain x E [0, 27], and derivatives given by COS X f' (x ) = sin x - 2 and f " (x) = -1 + 2 sin x (sin x - 2)2 Then: . f (x) has a local minimum at x = . f(x) has a local maximum at x = . f(x) is concave up over the interval (