t=1:9;
h=10.^(-t);
d1=(exp(h)-exp(-h))./(2*h);
Error1=ones(1,9)-d1;
d2=(exp(h)-exp(0))./h;
Error2=ones(1,9)-d2;
plot(1:9,log10(abs(Error1)),1:9,log10(abs(Error2)))

keyboard

tt=linspace(-1,-9);
hh=10.^(tt);
yy=(hh.^2/6)+(10^(-16))./hh;
plot(1:9,log10(abs(Error1)),1:9,log10(abs(Error2)),-tt,log10(yy))