% Example 12.3b (Physics 330)

% First build an array of function values

x=0:.01:10; y=cos(x);

% Then, since the function returns two arrays in the form
% [yp,ypp], you would use it this way:

[fp,fpp]=derivs(y,.01);

% look at the approximate derivatives

plot(x,fp,'r-',x,fpp,'b-')
title('Approximate first and second derivatives')