Quadratic equations are polynomials, meaning strings of math terms. An expression like “x + 4” is a polynomial. They can have one or many variables in any combination, and the magnitude of them is ...

Empirically estimated demand systems frequently fail to satisfy the appropriate theoretical curvature conditions. We propose and estimate two demand systems for which these conditions can be imposed ...

A good description of Least Squares Fit to Quadratic Data Part of a least squares fit involves solving three equations with three unknowns. Here is a description of using Excel's Solver to do this ...

In the general case the quadratic forms Qk determine many-electron functions formed from correlated electron orbitals of ellipsoidal symmetry and with variable centres. The results are easily extended ...