In this paper I study the oscillatory behaviour of equations (*) yi(t)+qy(t)+±17 piy(t- ri).0 and (**)yi(t)-gy(t) - i=1 i=1 where q?, 0, pi> 0 and ti 0, are constants, i=1, ,n. It each of the following conditions (1)pit exp(14-q ti) > 1 fo , n, (2) ( l pi) exp (1+q )2- >1, where = min Iry t2, A *Military Techinical College, Cairo. Egypt. Department of MatheMatics . of the forms p.y(t+r.1 )=Ds is proved that r some i,1=1,2, ../tn),(3) t(17p.)( S. )exp(n+q ti) 1, or (4) CZ' (q/n+ . ) j i > e implies iri i i i pi i T12 2 n implies i=1 i=1 that every solution of (*) or (**) oscillates. A generalization in the case where the coefficients q>, 0, pi) 0 1=1,...,n are continuous functions of t is also presented.
El ZANFALY, M. (1986). OSCILLATIONS OF FUNCTIONAL-DIFFERENTIAL EQUATIONS GENERATION BY SEVERAL RETARDED AND ADVANCED ARGUMENTS. The International Conference on Applied Mechanics and Mechanical Engineering, 2(2nd Conference on Applied Mechanical Engineering.), 183-200. doi: 10.21608/amme.1986.58999
MLA
Medhat El ZANFALY. "OSCILLATIONS OF FUNCTIONAL-DIFFERENTIAL EQUATIONS GENERATION BY SEVERAL RETARDED AND ADVANCED ARGUMENTS", The International Conference on Applied Mechanics and Mechanical Engineering, 2, 2nd Conference on Applied Mechanical Engineering., 1986, 183-200. doi: 10.21608/amme.1986.58999
HARVARD
El ZANFALY, M. (1986). 'OSCILLATIONS OF FUNCTIONAL-DIFFERENTIAL EQUATIONS GENERATION BY SEVERAL RETARDED AND ADVANCED ARGUMENTS', The International Conference on Applied Mechanics and Mechanical Engineering, 2(2nd Conference on Applied Mechanical Engineering.), pp. 183-200. doi: 10.21608/amme.1986.58999
VANCOUVER
El ZANFALY, M. OSCILLATIONS OF FUNCTIONAL-DIFFERENTIAL EQUATIONS GENERATION BY SEVERAL RETARDED AND ADVANCED ARGUMENTS. The International Conference on Applied Mechanics and Mechanical Engineering, 1986; 2(2nd Conference on Applied Mechanical Engineering.): 183-200. doi: 10.21608/amme.1986.58999
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