I'm trying to find least squares approximation $p(x)=c_1x+c_2x^2$ of $f(x)=xe^{x/2}$ in $[0,2]$.
Using the algorithm here, p.7.: http://www.math.niu.edu/~dattab/MATH435.2013/APPROXIMATION.pdf
I'm able to come up with a $3 \times 3$ matrix $S$ and $3 \times 1$ vector $b$. However this gives me as a solution three coefficients, even though I only have two. What do I need to do to get only two (i.e. no $c_0$)?