What is the derivative of a function?
The derivative of a function at a particular point measures the gradient of that function, and is defined as the gradient of the tangent line at that point. However there are basic rules that can be followed for quickly calculating a derivative. For instance take the function f(x)=x2, then the derivative of f(x), written dy/dx, is dy/dx=2x So the gradient of f(x)=x2 at the point x=2 is 4. More generally, the derivative of xn is nxn-1. There are various different rules that can be used to easily calculate the derivatives of more complicated functions.
