How to get the slope of a Interpolation[] function at a specified point?

*To*: mathgroup at smc.vnet.net*Subject*: [mg26589] How to get the slope of a Interpolation[] function at a specified point?*From*: liwen liwen <gzgear at yahoo.com>*Date*: Tue, 9 Jan 2001 01:52:03 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Dear Friends: How are you! I want to get the slope of a Interpolation[] function at a specified point, for example,here is a Interpolation function : geartable={{0,0},{1,1},{2,3},{3,4},{4,6},{5,7},{6,9.5},{7,12},{8,14}}; Gear=Interpolation[geartable]; y=Gear[4.5]; I want to get the slope of Gear function at the point of {4.5,y},what should I do ? Can I use the FunctionInterpolation[] to make out a precise function to find the slope value ? Is the FunctionInterpolation[] precise enough to get the very precise slope value ? Best Regards, Liwen E-mail: gzgear at yahoo.com __________________________________________________ Do You Yahoo!? Yahoo! Photos - Share your holiday photos online! http://photos.yahoo.com/