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9.3 The Chain Rule

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Question 38

The population NNN of a specific bacteria culture, in thousands, is modeled by the equation

N(t)=(2t+2)28+122t+23 N(t) = \frac{(2t+2)^2}{8} + 12\sqrt[3]{2t+2} N(t)=8(2t+2)2​+1232t+2​

for t≥0t \ge 0t≥0, where ttt is the time in hours since the start of an experiment.

a.

Find an expression for dNdt\frac{dN}{dt}dtdN​.

[3]
b.

The point PPP with coordinates (3,32)(3, 32)(3,32) lies on the graph of the population model. Find an equation of the tangent to the curve at the point PPP.

[4]
c.

Show that the model predicts no stationary points for the population for t≥0t \ge 0t≥0.

[2]
Markscheme

9.3 The Chain Rule Questions

  1. A Level
  2. /Maths
  3. /9.3 The Chain Rule

58 exam-style questions on Edexcel A Level Maths 9.3 The Chain Rule. Each one has a worked solution and a mark scheme showing where the marks go.

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