What is the product rule?
- The product rule is a formula that allows you to differentiate a product of two functions
- If where u and v are functions of x then the product rule is:
- In function notation, if then the product rule can be written as:
- The easiest way to remember the product rule is, for where u and v are functions of x:
- The product rule formulae are in the formulae booklet – make sure you know how to find them.
- Don't confuse the product of two functions with a composite function:
- The product of two functions is two functions multiplied together
- A composite function is a function of a function
- To differentiate composite functions you need to use the chain rule