The population of a luminescent algae colony, PPP, measured in thousands, is modelled by the function P(t)=4t−20t+25,t>0P(t) = 4t - 20\sqrt{t} + 25, \quad t > 0P(t)=4t−20t+25,t>0 where ttt is the time in hours since the colony was first observed.
Determine the values of ttt for which the population is exactly 9 thousand.
Find the value of ttt for which d2Pdt2=527\dfrac{d^2P}{dt^2} = \dfrac{5}{27}dt2d2P=275.
Practise Edexcel A Level Maths 9.9 Using Second Derivatives with exam-style questions for A Level Maths. 57 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.