clear all
t=[0 10 20 30 40 50 60]';
N=[5.31 7.24 9.64 12.87 17.07 23.19 31.44]';
c=log(N)
a1=sum(t(1:7))
a2=sum(c(1:7))
z=t.*c
w=t.*t
a3=sum(z(1:7))
a4=sum(w(1:7))
A=[a2;a3]
B=[a1,numel(t);a4,a1]
x=B\A