function P2_09A2
clear, clc, format short g, format compact
xguess = 0.505 ; 
disp('Variable values at the initial estimate');
disp([' Unknown value ' num2str(xguess) '   Function Value ' num2str(NLEfun(xguess))]); 
xsolv=fzero(@NLEfun,xguess); 
disp(' Variable values at the solution');
disp([' Unknown value ' num2str(xsolv) '   Function Value ' num2str(NLEfun(xsolv))]); 
%- - - - - - - - - - - - - - - - - - - - - -
function fV = NLEfun(V); 
P = 100; 
R = .08206; 
T = 300; 
nmoles = 2.5 * 1000 / V; 
Tc = 304.2; 
Pc = 72.9; 
a = 27 * R ^ 2 * Tc ^ 2 / (Pc * 64); 
b = R * Tc / (8 * Pc); 
fV = (P + a / (V * V)) * (V - b) - (R * T);