First of all i am new to Matlab, and not sure whether to use polyfit or something else for my problem.
I plotted a graph with the following matlab code:
t=transpose(linspace(-1,1,50)) y=1./(1+25*t.^2) n=10 A=fliplr(vander(t)) A=A(:,1:n) x=A\y u=linspace(-1,1,1000) g=x(n)*ones(1,1000) for $i=(n-1):-1:1 g=g.*u+x(i) end plot(u,g,'-',t,y,'o') Now my question is: plot the figure with polynomial fit of polynomial degree 2.
How should i do this?
Thanks
1 Answer
$\begingroup$So you want to fit y as a function of t, right? Use
p = polyfit(t,y,2);
fit = polyval(p,t);
plot(u,g,'-',t,y,'o',t,fit)
The first line is the built-in polynomial fit function. The number 2 is the degree which you specify and it returns the coefficients of the polynomial in p. Note degree 2 means three coefficients. The second line then evaluates the polynomial using the coefficients in p. And then the third, plots them all together.
$\endgroup$ 1
