# Exercise Solution 2.16

Recall that, for nonsingular square matrices ** h** and

*k*[s1]

Solution [2.103] for ordinary least squares assumes that columns of ** f** are linearly independent. If

*m*=

*l*, then

**is a nonsingular square matrix. Applying [s1] to solution [2.103], we obtain:**

*f*[s2]

which is solution [2.49] for ordinary interpolation.