how can one use mathematica get the approximate derivative of {x,y} data points?

*To*: mathgroup at smc.vnet.net*Subject*: [mg124309] how can one use mathematica get the approximate derivative of {x,y} data points?*From*: dr DanW <dmaxwarren at gmail.com>*Date*: Mon, 16 Jan 2012 17:12:57 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

The derivative curve you will get with Interpolation[]' can look very weird. I find I get better results using Interpolation[..., Method->"Spline"]'. The Spline function is continuous in first and second derivatives, so the resulting derivative is smoother. Daniel