8 marks] A Gompertz curve is often used to model growth. The following Gompertz curve models the growth of certain breast ancer tumours: N(t) = ec(1-e-*) = exp [c(1-e-kt)] here N(t) is the number of cancer cells after t days, and c and & are constants. Show that N' (t) =. ck exp [c (1 - e-kt)] and N" (t) = ck2 exp [c (1 - e-kt)] (c- ekt) ekt e2kt N' ( + ) =