Before we can look at how to differentiate a function of more than one variable, we need to recap the derivatives of the so-called standard functions.
These standard functions are: power functions, trigonometric functions, logarthmic functions and exponential functions. If you feel unfamiliar with one or more of these functions, have a look at the relevant MathHelp notebook in the 1st-level set.
We'll briefly look at each of these standard functions, and recap on the derivatives in each case.