The Chain Rule allows us to differentiate functions of the form f(g(x)) for example [math]y=\left(x^2+3x\right)^{^3}[/math][br][br]This function is a composition of [math]g\left(x\right)=x^2+3x[/math] and [math]f\left(x\right)=x^3[/math][br][br]The chain rule allows us to find the derivative of this if we can differentiate the individual component functions.[br][br]Try substituting some different component functions, you can use the tangent to the graph to check your derivative.