## Summary

In this paper Ezeilo's result*[2]* on the boundedness of solution of a certain fourth-order equation is extended to more general equations of the form*1.1*(*1*). A much shorther proof of an earlier existence result*[6]* for periodic solutions of*1.1*(*1*) is also given.

## References

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J. Cronin,

*Fixed points and Topological degree in*Non-*linear Analysis; Mathematical Surveys*N^{o}11 (American Math. Soc. 1964). - [2]
J. O. C. Ezeilo,

*On the boundedness and the Stability of Solutions of Some fourth-order equations*, J. Math. Analysis and Applications, Vol. 5, N^{o}1, August, (1962). - [3]
—— ——,

*A generalizated of a Boundedness Theorem for a certain third-order equation;*Proc. Camb. Phil. Soc. 63, (1957), pp. 735–742. - [4]
-- --,

*An elementary proof of a Boundndness Theorem for a certain third-order equation;*J. Lond. Math. Soc. (1963), pp. 11–16. - [5]
H. Shaefer, Math. Ann., 129, (1955), pp. 415–416.

- [6]
H. O. Tejumola andJ. O. C. Ezeilo,

*On the existence of periodic Solutions of certain fourth order differential Equations;*(To appear). - [7]
—— ——,

*Boundedness and Periodicity of Solutions of a certain system of third-order equations*, Ann. Math. Pura. Appl. IV, Vol. LXXIV, (1966), pp. 283–316. - [8]
E. C. Titchmash,

*The theory of Functions*, Oxford University Press, (1952). - [9]
T. Yoshizawa, Mem. Univ. Kyoto, Series A, 28, (1953), pp. 133–141.

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### Cite this article

Tejumola, H.O. Boundedness and periodicity of solutions of certain fourth-order differential equations.
*Annali di Matematica* **80, **177–196 (1968). https://doi.org/10.1007/BF02413628

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### Keywords

- Differential Equation
- Periodic Solution
- General Equation
- Existence Result
- Early Existence