esroot2.m

% script esmin1

f=inline('abs(3.*x.^4-32*x.^3+114.*x.^2-144.*x + 32)');
option=optimset('tolX', 1.0E-8);
s(1) = fminbnd(f, 0, 1, option)
s(2) = fminbnd(f, 2, 3, option)
s(3) = fminbnd(f, 3, 5, option)
x =linspace(0,5, 500);
plot(x,f(x));
axis([0,5,min(f(x))-5, max(f(x))]);
hold on
axis manual
plot(sol,0,'r+');
st = sprintf('minima  x = %7.4f, %7.4f et %7.4f, ',s);
text(0.2, -2, st, 'fontsize', 14);
title('fonction |3x^4-32x^3+114x^2-144x + 32|', 'fontsize', 14);