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

*To*: mathgroup at smc.vnet.net*Subject*: [mg124249] Re: how can one use mathematica get the approximate derivative of {x,y} data points?*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Sat, 14 Jan 2012 17:10:45 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

data = {#, Cos[#]} & /@ RandomReal[{0, 2 Pi}, 20]; f = Interpolation[data]; Plot[{f[x], f'[x]}, {x, Min[data[[All, 1]]], Max[data[[All, 1]]]}] Bob Hanlon On Sat, Jan 14, 2012 at 2:53 AM, Michael B. Heaney <mheaney at alum.mit.edu> wrote: > Hi, > > I have a set of {x,y} data points: > > {{0.03512, -0.5}, {0.0351181, -0.499}, ... {-0.113972, 0.699}, {-0.115072, > 0.7}} > > These data points look like a function y=f(x) when plotted on the x-y axes. > However, I do not know what the function f(x) is. But I need to get the > approximate derivative df/dx, as another set of data points. How can one > use Mathematica to do this? > > Thanks, > > Michael >