scholarly journals A bound for zeros of solutions to a higher order non-homogeneous ODE with polynomial coefficients

2021 ◽  
pp. 405-416
Author(s):  
M. I. Gil'
2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Michael Gil’

We consider the equationu″=P(z)u+F(z)  (z∈C), whereP(z)is a polynomial andF(z)is an entire function. Letzk(u)  (k=1,2,…)be the zeros of a solutionu(z)to that equation. Lower estimates for the products∏k=1j|zk(u)|  (j=1,2,…)are derived. In particular, they give us a bound for the zero free domain. Applications of the obtained estimates to the counting function of the zeros of solutions are also discussed.


2015 ◽  
Vol 98 (112) ◽  
pp. 199-210
Author(s):  
Maamar Andasmas ◽  
Benharrat Belaïdi

We investigate the growth of meromorphic solutions of homogeneous and nonhomogeneous higher order linear differential equations f(k) + k-1?j=1 Ajf(j) + A0f = 0 (k ? 2); f(k) + k-1 ?j=1 Ajf(j) + A0f = Ak (k ? 2); where Aj(z)(j=0,1,...,k) are meromorphic functions with finite order. Under some conditions on the coefficients, we show that all meromorphic solutions f ?/0 of the above equations have an infinite order and infinite lower order. Furthermore, we give some estimates of their hyper-order, exponent and hyper-exponent of convergence of distinct zeros. We improve the results due to Kwon, Chen and Yang, Bela?di, Chen, Shen and Xu.


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