This thesis project addresses two types of problems related with certain classes of differential equations matriarchal, such as the hypergeometric equation and the equation matriarchal matriarchal Ricati with coefficients of variables. The unifying element of memory is the method Frobenius matriarchal, which has already been used in the thesis doctoral M. Legua, R M. V. Ferrer and Company. The contribution This latest report is he marking error trncación of the solutions obtained in series, which to obtain two consequences of enormous interest in applications, such as: - Obtaining solutions computable in finite form. - The construction of approximate solutions to an accuracy preset. It must be said that the information I have, the analysis truncation error in terms of a fixed presicisión advance is not available in existing literature. In connection with the hypergeometric equation is matriarchal First get a couple of solutions to describe the general solution of (1.1) in terms of themselves, without considering the problem extended equivalent. Is also studied the truncation error when it gets solution in a series of initial value problem (1.1) and a representation of the function matriarchal hypergeometric function in terms of the Gamma matriarchal. The interest of the equation is a hypergeometric mergente continuation of the theory of polynomials otogonales matriarchal, because in the evaluation of the coefficients of the developments in series of orthogonal polynomials, they are expressed in terms of function hypergeometric. The Riccati equation is one of the most extensively studied for their emergence in classical and modern problems of theory control, as well as troubleshooting contour for linear systems (see the references in chapter devoted to the Riccati equation).