Doesn't plot 10^8 correctly in log fitting curve

Hello,

I am trying to fit data to log curve (I took the model from the matlab manual).

Everything is fine before coefficient in y reaches 10^8. At that point and beyond (10^9, 10^10) matlab doesn't fit the data.

What seems to be the problem? Screenshots of graphs attached.

Thanks you in advance!

x = [3 9 27 81 243 729 2187 6561];

y = 100000000*[0.0120 0.0360 0.1080 0.3217 0.8515 1.5367 2.0733 2.1704];

myfittype = fittype('a + b*log(x)',...

'dependent',{'y'},'independent',{'x'},...

'coefficients',{'a','b'})

myfit = fit(x',y',myfittype)

figure(1)

plot(myfit,x,y)

title('10^8 fitting')