function ChemEquil
% 求解化學平衡問題
% This program is used to demonstrate how to use function fsolve() 
% to solve a set of nonlinear equations
%
%   Author: HUANG Huajiang
%   Copyright 2003 UNILAB Research Center, 
%   East China University of Science and Technology, Shanghai, PRC
%   $Revision: 1.0 $  $Date: 2003/05/23 $

clear all
clc

x0 = [0.3  0.3  0];
x = fsolve(@NonlinEqs,x0)
fprintf('\t化學平衡時丙醛的摩爾分率為：%.3f %s',x(3)/(1+x(2)+x(3))*100,'%')

% ------------------------------------------------------------------
function f = NonlinEqs(x)
tmp1 = 1 - x(1) - x(2) - x(3);
tmp2 = 1 + x(2) + x(3);
f(1) = x(1)/tmp1 - 0.064;
f(2) = x(2)*(x(2)+x(3))/(tmp1*tmp2) - 0.076;
f(3) = x(3)*(x(2)+x(3))/(tmp1*tmp2) - 0.00012;