Simultaneous multiplicative property of the derivative and integral in functions of C¹ class.
Abstract
In 2015 the study entitled A multiplicative property of the derivative in $\mathcal{C}^{1}$ class functions} showed that given a function $f(x)$ of
$\mathcal{C}^{1}$ class, with $f(x)\neq\e{x}$, you can find a family of functions $\F_{f (x)}$ where $g(x)\in\F_{f(x)}$ if it satisfies that $\left[f(x).g(x)\right]'=f'(x).g'(x)$ (see [3]). In accordance with the mentioned study, and keeping as purpose to show to the Mathematics student (or any other science) that it is possible to perform research with simple structures, this article shows that given a function $f(x)$ of $\C^{1}$ class, there is a family of functions $\I_{f(x)}$ such that $g(x)\in\I_{f (x)}$ if it satisfies that $\displaystyle{\int [f(x).g(x)]\,dx=\int f(x)\,dx.\int g(x)\,dx}$. The existence of a family of functions $\SIF_{f(x)}$, such that $h(x)\in\SIF_{f(x)}$ if it simultaneously satisfies the multiplicative property of the derivative and the integral for a given function $f(x)$ of $\C^{1}$ class, is also studied.
References
Leithold, Louis. El Cálculo con Geometría Analítica. Editorial HARLA, Mexico, D.F. 1992.
Rosas, T. Una propiedad multiplicativa de la derivada en funciones de clase C¹. Aleph Sub-cero, Serie de divulgaciones. 1(2015), 81-102.
Rosas, T. C-ortocentros y sistemas C-ortocéntricos en planos de Minkowski. Aleph Sub-cero, Serie de divulgaciones. 2(2014), 104-132.
Rosas, T. Sistemas C-ortocéntricos y circunferencia de Feuerbach para cuadriláteros en planos de Minkowski. Boletín de la Asociación Matemática Venezolana, 22(2) (2015), 125-141.
Trucco, Sixto E. y Casparri de Rodríguez, María T. Ecuaciones Diferenciales. Ediciones Macchi, Cordoba - Buenos Aires, 2015.