A simple model for the cost of a car journey £ C C\,C when a car is driven at a steady speed of v v\,v mph is
C=4500v+v+10 C = \frac{4500}{v} + v + 10 C=v4500+v+10Use this model to find the value of v v\,v which minimises the cost of the journey.
Use d2Cdv2\displaystyle \frac{d^2C}{dv^2}dv2d2C to verify that C C\,C is a minimum for this value of vvv
Calculate the minimum cost of the journey
28 exam-style questions on Edexcel AS Level Maths Differentiation, covering 12.1 Gradients of Curves, 12.2 Differentiation from first principles, 12.3 Differentiating x^n, 12.4 Differentiating Quadratics, 12.5 Differentiating functions with two or more terms, 12.6 Gradients, Tangents and Normals, 12.7 Increasing and Decreasing Functions, 12.8 Second Order Derivatives, 12.9 Stationary Points, 12.10 Sketching Gradient Functions, and 12.11 Modelling with Differentiation. Each one has a worked solution and a mark scheme showing where the marks go.