%0 Journal Article %T Matrix Transformations and Quasi-Newton Methods %A Boubakeur Benahmed %A Bruno de Malafosse %A Adnan Yassine %J International Journal of Mathematics and Mathematical Sciences %D 2007 %I Hindawi Publishing Corporation %R 10.1155/2007/25704 %X We first recall some properties of infinite tridiagonal matrices considered as matrix transformations in sequence spaces of the forms sξ, sξ∘, sξ(c), or lp(ξ). Then, we give some results on the finite section method for approximating a solution of an infinite linear system. Finally, using a quasi-Newton method, we construct a sequence that converges fast to a solution of an infinite linear system. %U http://www.hindawi.com/journals/ijmms/2007/025704/abs/