I write this in matlab:
>> x=0.1:0.1:0.6
x =
0.1000 0.2000 0.3000 0.4000 0.5000 0.6000
y=[1.621 1.408 1.266 1.170 1.104 1.060];
>> k=log(y)
k =
0.4830 0.3422 0.2359 0.1570 0.0989 0.0583
>> l=log(x)
l =
-2.3026 -1.6094 -1.2040 -0.9163 -0.6931 -0.5108
and this our result:
>> z=diff(k)./diff(l)
z =
-0.2032 -0.2622 -0.2741 -0.2602 -0.2231
but in my book the result is different:
d ln(y) / d ln (x)= [ -0.246 - -0.249 - -0.2.44 -]
i must reach the book's result, but how?