Résumé:
In this thesis, we are interested in studying the growth of solutions of higher-order
linear di erential equations, speci cally focusing on conditions on coe cients
under which the solutions of these equations are of in nite order.
Firstly, we investigate the iterated order and iterated type of solutions of
these equations where their coe cients are entire and meromorphic functions.
Secondly, we study the hyper-order of analytic solutions of linear di erential
equations whose coe cients are analytic near an isolated singular point. We also
consider the non-homogeneous case.
Finally, we use a new idea to estimate the growth of solutions of linear differential
equations. We consider the coe cients of these equations as solutions
of certain second-order linear di erential equations
