MATLAB: Newton polynomial interpolating points, matrix too big

newton polynomial

Hi,
My code to make a newton polynomial and plot it does not work. I cannot figure out what the problem is. "Matrix dimensions must agree". It seems my matrix A grows too much.
f = @(x) x.^2.*sin(x);
x = [0 1 2 3 5 7 8];
y= f(x);
k = length(x)
ak=ones(k,1);
A = ak;
for column=2:k
ak = ak.*(x-x(column-1));
A =[A ak];
end
c=A\y
p =@(x) c(1) + c(2)*x + c(3)*x.^2+c(4)*x.^3;
tv = 0:0.1:6;
plot(tv, p(tv), 'r')
hold on;
plot(tv, f(tv), 'b')

Best Answer

  • Try changing this line
    c=A\y
    by
    c=A\y'