% Numerical Mathematics and Computing, Fifth Edition
% Ward Cheney & David Kincaid
% Brooks/Cole Publ. Co.
% (c) 2003
%
% file: inverse_interp.m
%
% It gives an example of inverse
% interpolation to find a zero of cosh x - 2.
%
x = [1.2 1.3 1.4 1.5]
y = cosh(x)-2
p = polyfit(y,x,3)
v = polyval(p,0)
t = cosh(v) - 2