False_Position_Methods

%False_Position_Methods

syms x
fx = x^2+x-3;
%fx = x^3-0.165*x^2+3.993*10^-4;
xl = 1;
xu = 2;
fxl = subs (fx,x,xl);
fxu = subs (fx,x,xu);
xr = (fxl*xu-fxu*xl)/(fxl-fxu);
n  = 100;
ea = 0.0001;
es = 1;
N  = [xl xu xr es];

for i = 1:n

fxl = subs (fx,x,xl);
fxu = subs (fx,x,xu);
xr = (fxl*xu-fxu*xl)/(fxl-fxu);
fxr = subs (fx,x,xr);

if fxl*fxr < 0
    es = abs((xr - xl)/xr);
    xu = xr;
else
    es = abs((xr - xu)/xr);
    xl = xr;
end

if es<ea
   break
end
N = [N; xl xu xr es];
end

N
x= 1:101;
plot (x',N(:,4),'O')
grid on