[Haskell-cafe] representing differencial equations in haskell

Hi there. Let's say I have mathematical model composed of several differential equations, such as : di/dt = cos(i) dc/dt = alpha * (i(t) - c(t)) (sorry my maths are really bad, but I hope you get the point) I would like to approximate the evolution of such a system iteratively. How would you do that in haskell ? cheers, Thomas