clc
clear all
x=[2 3 4 5]
X=log(x)
y=[27.8 62.1 110 161]
Y=log(y)
N=length(x)
M=[N sum(X); sum(X) sum(X.^2)]
%for element wise multiplication use . operator
B=[sum(Y); sum(X.*Y)]

L=inv(M)*B


f=exp(L(1))*x.^L(2)
plot(x,y,'*r')
hold on
plot(x,f,'b-')

% M1=[N sum(x) sum(x.^2); sum(x) sum(x.^2) sum(x.^3); sum(x.^2) sum(x.^3) sum(x.^4)]
% B1=[sum(y);sum(x.*y);sum(x.^2.*y)]
% L2=inv(M1)*B1
% f1=L2(1)+L2(2)*x+L2(3)*x.^2
% plot(x,f1,'k-')