function aprox
x=[0:5];
y=[1 2 3 5 9 10];
p1=0;
p2=0;
f=0;
for i=1:length(x)
    p1(i)=exp(x(i));
    p2(i)=1;
end
A=[p1*p1' p1*p2'; p2*p1' p2*p2'];
v=[p1*y'; p2*y'];
Q=inv(A)*v;
a=Q(1)
b=Q(2)
X=[0:0.01:5];
for i=1:length(X)
    f(i)=a*exp(X(i))+b;
end
plot(X,f,'-'),xlabel('x'),ylabel('y');
for i=1:length(x)
    p1(i)=(x(i))^2;
    p2(i)=x(i);
    p3(i)=1;
end
A=[p1*p1' p1*p2' p1*p3'; p2*p1' p2*p2' p2*p3'; p3*p1' p3*p2' p3*p3'];
v=[p1*y'; p2*y'; p3*y'];
Q=inv(A)*v;
a=Q(1)
b=Q(2)
c=Q(3)
X=[0:0.01:5];
for i=1:length(X)
    f(i)=a*(X(i))^2+b*X(i)+c;
end
hold on
plot(X,f,'-r'),xlabel('x'),ylabel('y');
plot(x,y,'*')
hold off