Another proof of the quadratic formula: comparison with the traditional proof and Po-Shen Loh's approach, and its use as a solution method. Otra prueba de la fórmula cuadrática: comparación con la prueba tradicional y la de Po-Shen Loh, y su uso como método de solución.

Abstract

This article proposes another proof of the general formula for solving in the complex numbers second-degree polynomial equations in one unknown with real coefficients, popularly known as quadratic formula. In addition, it analyzes the similarities and differences with the traditional proof that implements the technique of completing the square and with the proof proposed in recent years by mathematician Po-Shen Loh. Finally, it shows an example to illustrate the use of the algorithm from the demonstration as a solution method for this class of equations.