Date: Aug 1, 1996 2:07 AM
Author: Dwarf
Subject: Piecewise Functions
I am trying to use Mma to solve a model where the system behaves a

certain way up to a point, and an entirely different way after that

point. The result is something like:

f[x_/;x<4]:=0

f[x_/;x>=4]:=InterpolatingFunction<<...>>

This part I can get to work no problem. For part of my analysis, I would

like to take the derivative of the function, but all I get is an identity

In[5]

f'[x]

Out[5]

f'[x]

Can anyone help?

+----------------------------+

| | I understand mine's a risky plan,

| Greg Anderson | and your system can't miss

| dwarf@wam.umd.edu | but is security, after all a cause

| timbwolf@eng.umd.edu | or symptom of happiness.

| |

+----------------------------+ Dream Theater -- A Matter of Time