difference_quotient.py

#function [diff] = difference_quotient(f,x,h)
#  Accompanying program for the text
#
#     Classical and Modern Numerical Analysis:
#     Theory, Methods and Practice
#  by Azmy S. Ackleh, Edward J. Allen,
#     R. Baker Kearfott, and Padmanabhan Seshaiyer
#
#     (Taylor and Francis / CRC Press, 2009)
#
#
#  difference_quotient (f,x,h) returns the forward difference quotient of
#  f at x with stepsize h, as in formula (6.1), page 323 of the text.

def difference_quotient(f,x,h):
        return ( f(x+h) - f(x) )/h