The concentration, C in ng/ml of nicotine in the body t minutes after starting to smoke a cigarette can be approximated by C = f(t) = 4te-0.08t (a) Find f'(t) NOTE: Enter the exact answer. f' ( t ) = 4 e -0.08t - 0.32 e-0.08t . 4 t X (b) Find f(12) and f'(12) and give units. NOTE: Round your answers to three decimal places. X f(12) = 0.258 ng/ml X f'(12) = 16.315 (ng/m screenshot 2