(9/3/97) If you want to write a matlab routine that takes a function
as an argument, you include in the argument list a variable that represents
the function name. When you call the function, you should supply the name
of the function inside quote marks. For example:
function y=newt(f,df,x,n)
% newton's method newt(f,df,x,n)
% x is the initial guess; n is the number of iterations
% files f.m and df.m contain the function and its derivatives
% the function and derivative names f and df must be supplied in
% quotes, i.e. a call would be of the form, newt('sin', 'cos', .2, 4).
Your program will need to use feval to evaluate the functions.