How can I use differentiation to solve modelling questions?
- Derivatives can be calculated for any variables – not just y and x
- In every case the derivative is a formula giving the rate of change of one variable with respect to the other variable
- Differentiation can be used to find maximum and minimum points of a function (see Stationary Points)
- Therefore it can be used to solve maximisation and minimisation problems in modelling questions
Exam questions on this topic will often be divided into two parts:
- First a 'Show that...' part where you derive a given formula from the information in the question
- And then a 'Find...' part where you use differentiation to answer a question about the formula
Even if you can't answer the first part you can still use the formula to answer the second part.