% Input
t = [0,    5,    13,   24,   44,  63];
U = [15.0, 12.0, 9.0,  6.0 , 3.0, 1.5];
lnU = log(U);


[xData, yData] = prepareCurveData(t, lnU);
linjfit=fit(xData, yData, 'poly1');

coeff = coeffvalues(linjfit);
k = coeff(1);
m = coeff(2);

U_0 = exp(m);
T = - 1/k;

conf = confint(linjfit, 0.68);
u_k = k - conf(1, 1);
u_m = m - conf(1, 2);

u_U_0 = exp(m)*u_m;
u_T = u_k / k^2;

hold on
plot(t, lnU, 'O');

xvec = linspace(t(1), t(end));
yvec = polyval(coeff, xvec);

xlabel('Tid (s)');
ylabel('ln (U)');

plot(xvec, yvec);