Differentiation wrt time

1. Feb 24, 2010

a.mlw.walker

Hi I have an equation where x is a distance that varies with time, and i want to differentiate the expression again wrt to time, but I am struggling:

$$\frac{dT}{dx^{.}}=Ir^{2}x^{.}\left[\frac{-(r^{2}+x^{2}-l^{2})2r-4rx^{2}}{\sqrt{1-(\frac{r^{2}+x^{2}-l^{2}}{2rx})4r^{2}x^{2}}}\right]^{2}$$

i dont know how easy it is to spot, but the 'dx' of dT/dx has a dot above the x, and there is another x(dot) after the Ir^2

i want to differentiate wrt time, ie the x's become x dots and the x dots become x double dots.

but I am struggling to differentiate it because there is a quotient rule and a couple of product rules.

Can anyone see how to do this?